Solution: During the formation of chemical compounds or molecules, an element's valence or valency is measured in terms of its ability to combine with other atoms, which is known as its combining...
Solution: (a)Elements are Neon (10) Calcium (20) Nitrogen (7) Silicon (14) (b)Neon belongs to group 18, Calcium belongs to group 2, Nitrogen belongs to group 7 and Silicon belongs to group 14.
Solution: The answer of the following is: (a)X is in Group 17, period 3 and Y is in group 2 Period 4. (b)X is Non-metal and Y is metal
Solution: c) Y Oxide will be a fundamental element in nature. Ionic bonding results in the formation of a compound. d) The electron dot structure:
Solution: The answer: (c) 2Mg+O2 $\to$ 2MgO (d) MgO+ H2O $\to$ Mg(OH)2
Solution: Lewis structures, also known as Lewis dot formulas, Lewis dot structures, electron dot structures, or Lewis electron dot structures, are diagrams that depict the bonding between atoms in a...
Solution: The answer is: (a) Element is Magnesium (b) Electronic Configuration-2,8,2
Solution: The answer is Aluminium Group 13 Period 3
Solution: The answer of the following: Carbon Group 14 Period 2Helium Group 18 Period 1
Solution: The answer for the following are: Sodium Group 1 Period 3Phosphorus Group 15 Period 3
Solution: Only 63 elements were known at the time of Mendeleev's discovery. Mendeleev looked into the relationship between chemical characteristics and the atomic manes of elements in the periodic...
Solution: Inert gases could be included in Mendeleev's Periodic Table without causing any disruptions to the original order of elements. Noble gases, such as Helium, were known prior to Mendeleev's...
Solution: (a) Sodium (b) Calcium (c) Mercury and order of reactivity : Hg < Ca < Na
Solution: The arrangement in order required is Ge < Ga < Mg < Ca < K
Solution: The letter K represents element A. (Potassium). It would be possible to have the electrical configuration of element A (atomic number 19) as 2, 8, 8, 1. Because it has only one valence...
Solution: The names of the following are: MagnesiumSodiumChlorineLithium Metals from the following are- Magnesium, Sodium, Lithium.
Solution: The elements in question are all members of the same group and are sorted from left to right. As a result, their atomic radii are increasing in order of magnitude. a)Li>Be>F>N b)...
Solution: From electron arrangement X -2, 8, 2 Y -2, 8 Because Y has fewer energy levels than X, the atomic radius of Y will be less than that of the latter.
Solution: A belongs to Group 13, B belongs to Group 14, and C belongs to Group 2. A belongs to Group 13 and B belongs to Group 14. The values of A, B, and C are 3, 4, and 2, respectively.
Solution: Eka-silicon is a kind of germanium (Ge). It belongs to group 4 of Mendeleev's periodic table, and as a result, it has a valency of four. GeCl4 is the chemical formula for its chloride....
Solution: It is possible to find instances in Mendeleev ′s Periodic Table in which elements with higher atomic masses are put before ones with lower atomic masses, and vice versa. As a result, items...
Solution: Because of the following factors, hydrogen holds a unique place in the Modern Periodic Table. The outer electronic configuration of hydrogen and alkali metals is comparable because both...
Solution: Despite the fact that the atomic mass of Silicon is equal to the average of the atomic masses of Sodium and Chlorine, the elements do not have the same physical properties and hence cannot...
Solution: a) Metals include sodium, magnesium, aluminum, and potassium. Halogens include the elements F and Cl. There are two sets of elements in total.b) Mendeleev's law of periodicity is...
Solution: Triads are a type of arrangement of elements that is commonly found in nature. For example, the elements lithium, sodium, and potassium form a trio. These elements have atomic masses of...
Solution: The answer is (b) decreases Explanation: When we move from left to right in a period, the radius of the atom shrinks, and as a result, the size of the atom reduces as well.
Solution: The answer is (c) Valence Explanation: In the periodic table, advancing down a group does not result in an increase in the number of valence electrons present.
Solution: The answer is (b) (ii) and (iii) Explanation: Atomic radius, which is defined as the distance between the nucleus and the outermost orbital, is clearly displayed in photos ii) and iii),...
Solution: The answer is (b) Metalloid Explanation: Silicon has an electrical configuration of 2, 8, and 4 atoms. Considering that the outermost shell has just four electrons, it requires an...
Solution: The answer is (a) An element with atomic number 7 Explanation: The element with atomic number 7 has electron configuration 2,5, which means it has the ability to gain three electrons and...
Solution: The answer is (c) metalloids Explanation: Metalloids include the elements boron (B), silicon (Si), and germanium (Ge). Arsenic (As), antimony (Sb), tellurium (Te), polonium (Po), and...
Solution: Answer is (c) E2O3 Explanation: Aluminum is Al with an oxidation state of +3, it may be converted into Al3+, and it has a valency of +3. $Al_2O_3$ will be formed as a result.Gallium and...
Solution: The answer is b) Explanation: Li is located on the left side of the current periodic table in the second period, followed by berrylium. Fluorine is located directly across from Neon. As a...
Solution: The answer is (b) Na >Mg >Al >Si > Cl Explanation: Na has one electron in its valence shell, magnesium has two, aluminium has three, and chlorine has seven electrons in its valence shell....
Solution: Option d) is the answer. Explanation: Isotopes are elements that have the same atomic number but have different atomic masses, and they are classified as such. Isotopes have the same...
Solution: Option b) is the answer Explanation: Sodium has one electron, magnesium has two, and aluminum has three electrons in its outermost shell, whereas fluorine has seven electrons in its...
Solution: The answer is (c) K Explanation: Magnesium and calcium are both members of the group I, while sodium and potassium are members of a different group (II). Given that K has only one electron...
Solution: The answer is (c) K Explanation: Because atomic radii decrease from left to right during a period of time, K has the biggest atomic radii of all the elements. This is due to an increase in...
Solution: The answer is (d) F, O, N Explanation: As you move from left to right over a period, the radius of an atom grows. The atomic numbers (N7), O(8), and F(10) are listed in increasing sequence...
Solution:The answer is (d) P Explanation: The electronic configurations of Na, Al, Si, and P are 2,8,1, 2,8,3,2,8,4, and 2,8,5 for the elements in the periodic table. The number of valence electrons...
Solution: The answer is (b) L shell Explanation: There are two shells in period 18, designated as K and L.
Solution: The answer is b) group 14 Explanation: Carbon is an essential ingredient of all organic molecules that are members of the 14th chemical group.
Solution: The answer is (c) Group 18 Explanation: Because group 18 has all of its outermost shells entirely filled, any element having an electrical configuration falls into this category.
Solution: The answer is (c) A and C Explanation: Here A is Fluorine(Group 17), B is Sodium (Group 1), C is Chlorine (Group 17), D is Magnesium(Group 2) and E is Aluminium (Group 13). A and C are...
Solution: The answer is (b) B, C, D Explanation: The first period is dominated by the element with the highest atomic number, whereas the second period is dominated by elements B, C, and D.
Solution: The answer is (c) It has 18 vertical columns known as Groups Explanation: The modern periodic table is divided into 18 groups and seven periods. Columns are referred to as groups, while...
Solution: Answer: (b) (i), (ii) and (iii) Explanation:...
Solution: Answer: a) Germanium Explanation: Initially, Mendeleev designated unidentified elements as EKA- Boron, EKA- Aluminum, and EKA Silicon, which were later renamed Scandium, Gallium, and...
Answer: (c) (i) and (iii) Explanation: The reaction described here is a combination of displacement and redox reactions. The displacement reaction occurs when oxygen displaces hydrogen in ammonia,...
Answer: (d) Combustion of Liquefied Petroleum Gas (LPG) Explanation: Because a new compound is generated after burning, combustion is always accompanied by a chemical change, which is irreversible...
Arrangement: ICZN represents International Code of Zoological Nomenclature. It directs a uniform arrangement of zoological terminology.
Solution: The cross between the F2 progeny of the same plant is - Hence, the correct answer is (c) (ii) and (iii).
Solution – the arabari forests are the best example of the conserved forest. This has happened because of the involvement of the forest department. The forest department included the localities to...
Solution – importance of forest as a resource – Forest provides habitat to numerous wildlife It protects wild life and provide them with food . It balances the oxygen and carbon dioxide level in the...
Solution – waste water can be used in following ways : Can be used for irrigation Can be used to water the plants in the garden Municipal water can be used for washing of the vehicles Municipal...
Solution – life without water cannot be even thought of because all life processes are dependent on water . So , yes conservation of water is very necessary . We all know that Earth has ¾ of...
Solution – activities performed are : Switching off the lights and fans when not in use Walking to the near by places .Close the taps when not in use Use of solar energy wherever possible . Using of...
Solution – explanation of the terms with examples – Reduce – when the use of the material or substance is lowered . For eg. Electricity , petroleum Recycle – when the used material is converted into...
(b) Which has an advantage over the other and why? Solution – ( a )Figure 16.1 (a ) is a pond ecosystem . Figure 16.1 (b ) is an underground water body . ( b ) ground...
Solution – methods to control carbon dioxide level in atmosphere – Encouraging the use of public transportation in place of private vehicles .Use of CNG .Planting of more trees .Pollution check of...
Solution – formation of coal and petroleum requires million of years . Demand of petroleum is more than its production . So if we do not cut off its usage it will be depleted soon . This is the...
Solution – measure taken to conserve electricity in your house are – Switch off all the lights and fans and other electric appliances when not in use .Keeps window open for natural sunlight .Replace...
Analyse the situation and give reasons for excessive growth of plants and death of fish in the lake. Solution – the fertilizers used for irrigation had spread into the lake water . The chemicals...
Solution – advantages of water harvesting at community level are – It reduces the use of ground water .It protects from storm water runoff . It reduces the damage to the creeks and water habitats...
Solution – list of things used in school daily – paper , pen , pencil ,eraser , bag , steel lunch box , steel water bottle , compass and divider ( made of metal ) , List of things that can be...
(i) hold water for irrigation (ii) hold water and prevent soil erosion (iii) recharge groundwater (iv) hold water permanently (a) (i) and (iv) (b) (ii) and (iii) (c) (iii) and (iv) (d) (ii) and (iv)...
(a) Using a car for transportation (b) Using polybags for shopping (c) Using dyes for colouring clothes d) Using windmills to generate power for irrigation Correct option- ( d ) Explanation - use of...
(a) Wind, ocean and coal (b) Kerosene, wind and tide (c) Wind, wood, sun (d) Petroleum, wood, sun Correct option – ( c ) Explanation – coal , kerosene , petroleum all has fossil fuel . While wind...
(a) grain storage (b) wood storage (c) water harvesting (d) soil conservation Correct option – ( c ) Explanation - Khadins, Bundhis, Ahars and Kattas are all examples of water harvesting that...
(a) social reasons (b) economic reasons (c) environmental reasons (d) all the above Correct option – ( d ) Explanation – construction of large dams are opposed on large scale . It is so because if...
(a) afforestation (b) thermal power plants (c) loss of forest, and decreased rainfall (d) cropping of high water demanding crops Correct option – ( b ) Explanation – ground water will not ...
(a) Teak (b) Sal (c) Bamboo (d) Mangroove Correct option – ( b ) Explanation – Ion Bengal the arabari forests have dominant vegetation of sal ( Shorea robusta ) . It is a commercial crop which is...
(a) Forests provide a variety of products (b) Forests have greater plant diversity (c) Forests do not conserve soil (d) Forests conserve water Correct option – ( c ) Explanation – Forests perform a...
(a) Mango tree (b) Snake (c) Wind (d) Wooden house Correct option – ( d ) Explanation - wooden house is not a natural resource as it is made by human being for its own use . While others...
(a) Economic development is linked to environmental conservation (b) Sustainable development encourages development for current generation and conservation of resources for future generations (c)...
(a) Governmental Agency for Pollution Control (b) Gross Assimilation by Photosynthesis (c) Ganga Action Plan (d) Governmental Agency for Animal Protection Correct option – ( c ) Explanation – GAP...
(i) Terrestrial flora and fauna of the area is destroyed completely (ii) Dislocation of people and domestic animals living in the area (iii) Valuable agricultural land may be permanently lost (iv)...
(a) to involve the community in forest conservation efforts (b) to ignore the community in forest conservation efforts (c) to cut down forest trees for developmental activities (d) government...
(a) protection of animals at the highest trophic level (b) protection of only consumers (c) protection of only herbivores (d) comprehensive programme to protect all the physical and biological...
(a) biodiversity in the area (b) monoculture in the area (c) growth of natural forest (d) preserves the natural ecosystem in the area Correct option – ( b ) Explanation – monoculture is the practice...
(i) Planned growth with minimum damage to the environment (ii) Growth irrespective of the extent of damage caused to the environment (iii) Stopping all developmental work to conserve the environment...
Biodiversity refers to the different species of flora and fauna present in an areaBiodiversity refers to only the flora of a given areaBiodiversity is greater in a forestBiodiversity refers to the...
(a) recycle, regenerate, reuse (b) reduce, regenerate, reuse (c) reduce, reuse, redistribute (d) reduce, recycle, reuse Correct option – ( d ) Explanation – to conserve the natural resources...
(a) 6.5 – 7.5 (b) 2.0 – 3.5 (c) 3.5 – 5.0 (d) 9.0 – 10.5 Correct option – ( a ) Explanation – for the life of the freshwater plants and animals the pH of water should neither be acidic nor basic ,...
(a) Soap and detergent factory (b) Lead battery manufacturing factory (c) Plastic cup manufacturing factory (d) Alcohol distillery Correct option – ( d ) Explanation – alcohol distillery is...
(a) disposal of unburnt corpses into water (b) discharge of effluents from electroplating industries (c) washing of clothes (d) immersion of ashes Correct option – ( a ) Explanation – human excreta...
(a) present only on land (b) a gift of nature which is very useful to mankind (c) a man-made substance placed in nature (d) available only in the forest Correct option – ( b ) Explanation –...
(a) water (b) forests (c) wind (d) sunlight Correct option – ( b ) Explanation – water , wind and sunlight are natural resources but they are non- exhaustible resources . The forests are also...
(a) Soil (b) Water (c) Electricity (d) Air Correct option – ( c ) Explanation – electricity is man made resource while soil , water and air are natural resources bestowed to us by the nature...
Solution – harmful effects of agricultural practices on the environment are – Loss of the fertility of the soil by cropping which can also cause soil erosion .Decrease in the underground water level...
Solution – oxides of sulphur and nitrogen are the by – products of the fertiliser industry . Other products include solid , liquid chemicals and some solid waste materials . These results in massive...
Solution – the main waste of the fertilizer industry are the effluents and the harmful gases .To manage the waste emitted by the fertiliser industries following measures can be opted : Some...
Solution – waste generated in the house and methods used for their disposal are – Waste materialMethod of disposalMilk pouches , poly bagsSafe disposal of plastic bagsDirt and sweeping wasteShould...
Solution Food chain Food webit is a natural system through which energy is transferred from one organism to the other . It comprises of numerous inter connected food chains . Instability of the...
Solution – the four activities which are eco – friendly in our daily life are – Harvesting of rain water Walking for short distances Using of public transport or encouraging sharing in place of use...
Solution – micro – organisms which break down the dead and decaying waste products are known as the decomposers . They break down the complex organic substances into simpler ones . These substances...
Solution – the flow of energy via living things in an ecosystem is known as the energy flow . All living organisms are categorized into producers and consumers . Further these producers and...
Solution – pond or a lake is a natural ecosystem so its complete and does not require and cleaning from outside . While an aquarium is an artificial incomplete ecosystem , which needs regular...
(a) Biomagnification — Accumulation of chemicals at the successive trophic levels of a food chain (b) Ecosystem — Biotic components of environment (c) Aquarium — A man-made ecosystem (d) Parasites —...
Solution – dead and decaying living matter is broken down by the decomposers present in the environment . They recycle dead animals into chemical nutrients . This aids to maintain the flow of the...
(a) The physical and biological world where we live in (b) Each level of the food chain where the transfer of energy takes place (c) The physical factors like temperature, rainfall, wind and soil of...
Solution - Biodegradable substancesNon-biodegradable substancesIt refers to any substance that is capable of undergoing biodegradationBy non biodegradable we mean any substance or material that...
Solution: The seeds of F1 plants are round and yellow. In the F2 generation, crossing between generations can result in new combinations of round-yellow, round green, wrinkled yellow, and...
Solution: The following are the basic characteristics of the inheritance mechanism: Characters are controlled by genesGenes exist in two or more formsOne gene form may be dominant over...
Solution: In the F2 progeny, the characters are RrYy x RrYy So, the cross will be- RYRyrYryRYRRYY Round and yellowRRYy Round and yellowRrYY Round and yellowRrYy Round and yellowRyRRYy Round and...
Solution: RrYy- Round and yellow rryy- Wrinkled and green RRYY- Round and yellow ryryryryRYRrYy Round and yellow seedsRrYy Round and yellow seedsRrYy Round and yellow seedsRrYy Round and yellow...
CrossProgenyRR YY x RR YY ……………………… Round, yellow x Round, yellow Rr Yy x Rr Yy ……………………… Round, yellow x Round, yellow rr yy x rr yy ……………………… wrinkled green x wrinkled, green RR YY...
Solution: Morphological structures are structures that are visible to our eyes. Molecular structures are biomolecules that are essential parts of living organisms. We are surrounded by a lot of...
Solution: Our bodies' responses to external stimuli such as diet, disease, and climate change result in acquired traits. This leads to the emergence of a specific attribute characterised by...
Solution: The differences between inherited and acquired characters are- Inherited CharactersAcquired CharactersCharacter traits are passed down from parents to their children.Characters that exist...
Solution: Although all human races appear to be distinct, they all share a common ancestor. The evidence in support of this viewpoint is as follows. • Brain size is similar. • Bipedal movement • The...
Solution: This is a controversial subject as it all depends on how we assess evolution. If the body's complexity is a criterion, humans are considerably superior to germs. Bacteria organise...
Solution: Genetic drift occurs when individuals of a species are isolated geographically. This restricts the segregated population's sexual reproduction. Separated individuals reproduce among...
Solution: The fact that a woman has only one daughter suggests that the egg has always acquired the X chromosome from the sperm. If sperm contributes X chromosomes, the child will be female;...
Solution: Pea plants were chosen for Mendel's experiments because they are easy to grow, have a short life period, and produce larger flowers. Pea plants are also self-pollinated.
Solution: The following are the pair of contrasting traits of the following characters in pea plant – Yellow is the dominant one whereas Green is the recessive allele. Round is the dominant one...
Solution: Animals do not share a common ancestor, even though they have a wide range of structures. This is because shared ancestry can severely limit diversity. Since many of the creatures share...
Solution: Homologous structures have the same basic structure as each other but serve different functions. Reptiles, amphibians, and mammals, for example, have forelimbs. If they don’t have common...
Solution: Due to the following factors, a very small population of a species faces a greater chance of extinction than a larger population- Inbreeding: Inbreeding is encouraged by a small...
Solution: The gamete donated by the male determines the sex of the baby. The 23rd pair of chromosomes in males are X and Y. The proportion of X to Y is 1:1 As a result, the chances of having a...
Solution: In their 23 pairs of chromosomes, females have XX. Since each gamete receives one X chromosome during meiosis, all-female gametes have one X chromosome.
Solution: The three important features of fossils that help in the study of evolution- Fossils are ancient organisms that have been preserved.Fossils aid in the identification of evolutionary...
Solution: The chromosome supplied by the father will determine the sex of a newborn. Mothers' 23rd chromosomal pair contains XX, and they always donate one X. Fathers, on the other hand, have the X...
Solution: The individual's sex is decided by the genes he or she got from their parents. If a baby inherits X chromosomes from the father, the child will be female; if the newborn receives Y...
Solution: Dinosaurs had feathers, but they couldn't fly. The feathers were later developed for flight by birds. Dinosaurs were reptiles, which indicates that birds descended from them. So, the...
Solution: The rules of heredity were suggested by Mendel, also Morgan was the first to discover a mutation in drosophila. The use-and-disuse idea was proposed by Lamarck. So, the correct answer is...
Solution: The sex of the offspring is determined by the 23rd pair of chromosomes, which is why it is termed a sex chromosome. So, one pair of chromosomes determines the sex of the individual. So,...
Solution: Progenies with the genotypes below would result from a cross between pure tall plant (TT) and short plant (tt). TT (Pure tall), tt (Pure short), and Tt (Pure short) ( Mixed tall). This...
Solution: Since genes code for specific proteins, statement ii) is incorrect. Because chromosomes can have any number of genes, Statement 4 is incorrect. Hence, the correct answer is (b) (i) and (iii)
Solution: This is the explanation for one progeny's expression in one version and another progeny's expression in another. So, the answer is (b) two different chromosomes.
Solution: The body's nature is determined by a person's eating habits. Regular exercise aids in the development of a muscular physique. Because bodily nature is not passed along to kids, the body...
Solution: Several generations of DNA variation result in the formation of new species. Since there are no gametes involved in asexual reproduction, there will be no variety. Individual movement...
Solution: Since species is the lowest taxon, members of the same species have the greatest number of shared features. So, the correct answer is (a) two individuals of a species.
Solution: Both parents contribute DNA to their offspring, and hence both parents contribute traits to their progeny. So, the correct answer is (c) both maternal and paternal DNA.
Solution: Since only useful variation has a chance of surviving, statement a) is incorrect. To survive, nature selects the most adaptable variant. This is Darwin’s theory of Natural selection. So,...
Solution: Deep in the soil, older fossils can be unearthed. As a result, option b) is the correct response. So, the answer is (b) the extinction of organisms has occurred thousands of years ago.
Solution: Due to similar design and origin, a pea plant's tendon and an Opuntia phylloclade are homologous. So, the correct answer is (a) Tendril of a pea plant and phylloclade of Opuntia are...
Solution: They both have a similar structure and grow beneath the earth's surface ( Roots). So, the correct answer is (c) Radish and carrot.
Solution: Evolution will not occur until the genetic material changes and alters. As a result, the evolution of new species necessitates changes in genetic material and chromosome variety. So, the...
Solution: Option b) is incorrect because weight loss and growth are influenced by external causes rather than hereditary factors. So, the correct answer is (b) Reduction in weight of the organism...
Solution: The egg zygote will develop into a male offspring if sperm containing the Y chromosome fertilizes it. The egg zygote will develop into a female child if sperm with the X chromosome...
Solution: The egg zygote will develop into a male offspring if sperm with the Y chromosome fertilizes it. The egg zygote will develop into a female child if sperm with the X chromosome fertilizes...
Solution: Due to the half size of the Y chromosome, they are sex-determining chromosomes that are not properly paired. So, the correct answer is (c) (iii) and (iv).
Solution: Since round and yellow are the prominent traits, all seeds in the first generation will be round and yellow. So, the correct answer is (a) round and yellow.
Solution: Option d is incorrect since every protein, enzyme, and hormone is regulated by a specific gene, whereas fats are not controlled by a gene. So, the correct answer is (d) for every molecule...
Solution: Only dominant traits are expressed in the first progeny of a monohybrid cross. So, the correct answer is (a) tallness is the dominant trait.
Solution: If the cross is between red and white flowers, only then will offspring be pink in colour. So, this is only possible if there is cross-fertilization. Hence, the correct answer is (c)...
Solution: Other methods, other than sexual reproduction, include a sort of asexual reproduction in which only one parent is involved. As a result, genetic material is exchanged during sexual...
Soln: Pollination Fertilization Pollen grains are transferred from the anther to the stigma of a flower. It is the result of the union of male and female gametes. Achieved by natural forces such as...
Soln: The ovary produces female gametes. Anthers produce male gametes.
Solution: Yes, Planaria are parasitic organisms that live in quiet ponds or bodies of water as free-living flatworms. They have the unusual ability to regenerate, which means they can develop new...
Soln: Since only one parent is involved in budding, fragmentation, and regeneration, and no gametes are formed, these kinds of reproduction are classified as asexual. Regeneration of Planaria Fig -...
Fig 8.3 Soln: 1. Ovary 2. Oviduct or fallopian tube 3. Uterus 4. The vaginal canal
bio Soln: A seed consists of an embryo and food that has been enclosed in a protective seed coat. Cotyledons and endosperm may contain the stored food. A plumule and radicle, located on opposing...
Soln: Sexually transmitted illnesses are diseases that pass from one person to another through sexual contact. Bacterial infections like gonorrhoea and syphilis, as well as viral infections like...
Soln: Predation and competition for food are prevalent. Species would have gone extinct if there was no reproduction. As a result, reproduction is tied to a species' population. The lineage of new...
Soln: One egg is discharged from each of the ovaries once a month. The egg is moved from the ovaries to the fallopian tube. Only one sperm can access the egg at a time when sperm move towards the...
solution: Physical devices such as the diaphragm (or cap) and condoms are employed in the barrier methods of preventing pregnancy. Human females wear a diaphragm (or cap) that covers their cervix....
Soln: The placenta is a disc that is embedded in the uterine wall during pregnancy. On the embryo's side of the tissue, there are villi. The villi are surrounded by blood gaps on the mother's side....
Soln: GameteZygoteFormed after MeiosisFormed by the fusion of two gametes.Gametes produce a haploid number of chromosomesproduces a diploid number of chromosomesMale and female parts produce...
Soln: Sexual reproductionAsexual reproductionTwo parents are involvedA single parent is involvedGametes are formedGametes are not formed When compared to asexual reproduction, there is more...
Soln: An egg and its zygote have a chromosomal number ratio of 1:2. The father's genetic material is found in sperm, whereas the mother's genetic material is found in eggs. The X or Y chromosome can...
Soln: The benefits of using mechanical barriers during sexual acts are- Mechanical barriers help to avoid unintended pregnancies andMechanical barriers help to avoid sexually transmitted...
Soln: Following the implantation of the young embryo, the uterus undergoes the following changes. • The uterine lining thickens to support the growing embryo (PLACENTA). • The uterine lining...
Soln: If fertilisation does not occur, the following changes occur in the uterus: • The extra lining of the uterus degenerates • Uterus lining fragments are evacuated through the vaginal canal • The...
Soln: The sequence of organs in the male reproductive system for transport of sperms is testis → epididymis → vas deferens → prostate→ urethra. Glands associated with the male reproductive...
Soln: The term "general growth" refers to the expansion of one's physical size. The ability to reproduce is the goal of sexual maturation. Sexual maturity is reached at a stage of life called...
Solution: Predation and competition for food are prevalent. Species would have gone extinct if there was no reproduction. As a result, reproduction is tied to the species' population.
Soln: Since the pollen grains are transferred to the ovary where the egg is located and fertilization takes place there, the zygote will be found in the ovary after fertilization.
Soln: Meiosis is a cell division process that involves halving the number of chromosomes. Chromosomes become equal to those of somatic cells after fertilisation. Mitosis occurs for the duration of a...
Soln: Pollination is the process of pollen grains being transferred from anthers to the stigma. There will be no fusing of gametes if pollination does not occur, and fertilisation will not occur.
Soln: Since the number of chromosomes in both gametes is the same, the number of chromosomes in a female tobacco plant gamete is 24. So, in a zygote, the total number of chromosomes is 48.
Soln: AnimalsChromosome numbersPlantsChromosome numbersMan46Corn20Cat38Cotton52Horse64Garden pea14Rabbit44Mango40Elephant56Onion16 1. The number of chromosomes has nothing to do with the size of the...
Soln: The two reasons for the appearance of variation among the progeny formed by sexual reproduction- Crossing over occurs during meiosis, andTwo individuals of the same species contribute...
Soln: Moisture is required for bread mould spores to develop and grow. As a result, mould thrives on a moist slice of bread.
Soln: Yeast requires energy to grow and divide its cells. Water lacks the necessary energy, whereas sugar does, therefore yeast thrives in a sugar solution.
Soln: Since chromosomes are halved during gamete development, the number of chromosomes in an organism's somatic cells remains the same. A diploid number of chromosomes refers to the halves of...
Soln: Clone is an asexually created collection of cells or organisms. Since there is no exchange of gametes during asexual reproduction, the offspring look similar to their parents.
Soln: Reproduction is the process of creating a new individual. Cell division results in the production of new individuals in unicellular organisms. In unicellular creatures, cell division is thus a...
Soln: The removal of the stamen, or male reproductive part of the flower, does not affect the plant's ability to produce flowers because the pistil, or female reproductive part, remains intact. As a...
Soln: Sexually transmitted bacterial infections such as syphilis caused by Treponema pallidum and Gonorrhoea caused by Neisseria gonorrhoeae. HIV is the virus that causes AIDS, which is a sexually...
Soln: The tube that joins the testes to the urethra is known as the Vas deferens. The vas deferens is a coiled conduit that transports sperm from the epididymis to the urethra and ejaculatory duct....
Soln: Gonads have two functions: hormone production and gamete production. Testes produce sperm and testosterone in males. The testis is a male reproductive organ but estrogen is produced in...
Soln: The temperature of the testes must be lower than the body temperature when they are laying in the scrotum. This is because the process of sperm formation requires an optimum temperature that...
Soln: Adolescence is a period of transition from childhood to adulthood. During adolescence following changes occur in girls- • Hair growth in new areas of the body, such as armpits, between the...
Soln: Adolescence is a period of transition from childhood to adulthood. Boys go through the following changes: • Hair growth in new areas of the body, such as armpits, chest, and between thighs...
Soln: Other life activities are required to keep the organism alive, while reproduction is required to maintain the species' lineage. Therefore, the correct answer is (d) to continue the species...
Soln: A zygote is formed when a male gamete fertilised the female gamete in case of sexual reproduction, to make new progeny. Offspring have more variants as a result of the...
Soln: Sexual reproduction is a process that involves two parents and produces two types of gametes, male and female. During fertilisation, the gametes combine to produce the zygote. This is a...
Soln: Unisexual flowers bear only male or female flowers, never both at the same time. As there is just one sex, cross-fertilization occurs, in which gametes are produced by two separate plants....
Soln: Answer is (d) (ii) and (iv) Flowering plants, often known as Angiosperms, bear flowers as a feature. They are not produced by other plants such as Bryophytes, Pteridophytes, and...
Soln: The pollen grain is placed on the flower's stigma. If the pollen grain and the stigma are compatible, the pollen grain germinates on the stigma, taking advantage of the moisture and nutrients...
Soln: A large number of spores ensures that even in difficult conditions, a few spores survive. The bread's moisture and nutrients give the perfect habitat for the spore to develop into mould. So,...
Soln: Plants use vegetative propagation, which is a sort of asexual reproduction. Plants' vegetative components, such as roots, stems, leaves, and buds, are used in vegetative reproduction to make...
Soln: Hyphae are tiny blob-on-a-stick-like structures involved in reproduction. The blobs are called sporangia, and they contain cells, or spores, that can develop into more Rhizopus individuals in...
Soln: During the formation of gametes, the number of chromosomes in the parents is halved and when these gametes fuse with the other gamete during fertilization, they restore the normal number of...
Soln: In sexually reproducing flowers the male (pollen grains) need to meet the female gamete (ovule). So, for the fusion of the male and female gamete, the pollen grains must reach the stigma, and...
Soln: Plasmodium divides into multiple daughter cells during cell division and this process is known as multiple fission. The process of plasmodium reproduction is known as binary multiple fission....
Soln: Spirogyra reproduces by the process of fragmentation which is a type of asexual reproduction. It breaks up the filaments into smaller pieces upon maturation and these pieces are known as...
Soln: Amoeba reproduces by binary fission, whereas Spirogyra reproduces by fragmentation, and yeast reproduces by budding. So, all these are different types of asexual reproduction. Therefore, the...