AutotrophsHeterotrophsThey have the ability to prepare their own meals.They cannot make their foodEx: Plants and certain bacteriaEx: Animals, Fungi and protozoans
42. Differentiate between an autotroph and a heterotroph
read more
NCERT Exemplar
41. Why do fishes die when taken out of water?
Only dissolved oxygen allows fish to breathe. When we remove fish from the water, they are unable to breathe owing to a lack of dissolved oxygen, and they die.
40. If a plant is releasing carbon dioxide and taking in oxygen during the day, does it mean that there is no photosynthesis occurring? Justify your answer.
If a plant is releasing carbon dioxide and taking in oxygen during the day, it is respiring; yet, this does not rule out the possibility of photosynthesis. This is due to the fact that...
39. Two green plants are kept separately in oxygen-free containers, one in the dark and the other in continuous light. Which one will live longer? Give reasons.
Because plats release CO2 during respiration, plants kept in constant light live longer. In the instance of a plant kept in the dark, CO2 causes a lack of oxygen, causing the plant to die sooner.
38. How do the guard cells regulate opening and closing of stomatal pores?
The introduction of water into guard cells aids in the opening of guard cells. The guard cell becomes turgid as a result of this. Water leaking from guard cells aids in the closing of guard cells....
“All plants give out oxygen during day and carbon dioxide during the night”. Do you agree with this statement? Give reason.
The statement is incorrect because plants respire and expel carbon dioxide at all times, but they only give out oxygen during the day because photosynthesis can only occur in the presence of sunlight.
36. Name the following
(a) The process in plants that links light energy with chemical energy (b) Organisms that can prepare their own food (c) The cell organelle where photosynthesis occurs (d) Cells that surround a...
35. During deficiency of oxygen in tissues of human beings, pyruvic acid is converted into lactic acid in the
(a) cytoplasm (b) chloroplast (c) mitochondria (d) Golgi body Answer is (a) cytoplasm Explanation: When there is a deficiency in oxygen Pyruvate is broken down in the cytoplasm of muscle cells,...
34. Choose the correct path of urine in our body
(a) kidney → ureter → urethra → urinary bladder (b) kidney → urinary bladder → urethra → ureter (c) kidney → ureters → urinary bladder → urethra (d) urinary bladder → kidney → ureter → urethra...
33. Lack of oxygen in muscles often leads to cramps among cricketers. This results due to
(a) conversion of pyruvate to ethanol (b) conversion of pyruvate to glucose (c) non-conversion of glucose to pyruvate (d) conversion of pyruvate to lactic acid The answer is (d) conversion of...
32. Which of the following statement(s) is (are) correct?
(i) Pyruvate can be converted into ethanol and carbon dioxide by yeast (ii) Fermentation takes place in aerobic bacteria (iii) Fermentation takes place in mitochondria (iv) Fermentation is a form of...
31. Which is the first enzyme to mix with food in the digestive tract?
(a) Pepsin (b) Cellulase (c) Amylase (d) Trypsin Answer is (c) Amylase Explanation: Amylase is produced in the mouth and acts on starch to break it down into smaller molecules. As a result, Amylase...
30. Choose the forms in which most plants absorb nitrogen
(i) Proteins (ii) Nitrates and Nitrites (iii) Urea (iv) Atmospheric nitrogen (a) (i) and (ii) (b) (ii) and (iii) (c) (iii) and (iv) (d) (i) and (iv) The answer is (b) (ii) and (iii) Explanation:...
29. The opening and closing of the stomatal pore depends upon
(a) oxygen (b) temperature (c) water in guard cells (d) concentration of CO2 in stomata The answer is (c) water in guard cells Explanation: The introduction of water into guard cells aids in the...
28. Choose the event that does not occur in photosynthesis
(a) Absorption of light energy by chlorophyll (b) Reduction of carbon dioxide to carbohydrates (c) Oxidation of carbon to carbon dioxide (d) Conversion of light energy to chemical energy Answer is...
27. Which of the following equations is the summary of photosynthesis?
(a) 6CO2 + 12H2O → C6H12O6 + 6O2 + 6H2O (b) 6CO2 +H2O + Sunlight→C6H12O6 + O2 + 6H2O (c) 6CO2 + 12H2O + Chlorophyll + Sunlight→ C6H12O6 + 6O2 + 6H2O (d)...
26. The internal (cellular) energy reserve in autotrophs is
(a) glycogen (b) protein (c) starch (d) fatty acid The answer is (c) starch Explanation: Animals store energy in the form of glycogen, while plants store energy in the form of starch.
25. Which of the following is an incorrect statement?
(a) Organisms grow with time (b) Organisms must repair and maintain their structure (c) Movement of molecules does not take place among cells (d) Energy is essential for life processes The answer is...
24. The blood leaving the tissues becomes richer in
(a) carbon dioxide (b) water (c) haemoglobin (d) oxygen The answer is (a) carbon dioxide Explanation: Carbon-dioxide accumulates in tissues as a result of respiration. As a result, the...
23. Oxygen liberated during photosynthesis comes from
(a) water (b) chlorophyll (c) carbon dioxide (d) glucose The answer is (a) water Explanation: Water molecules split during photosynthesis to produce oxygen and hydrogen ions. Plants emit oxygen,...
22. The filtration units of kidneys are called
(a) ureter (b) urethra (c) neurons (d) nephrons The answer is (d) nephrons Explanation: The functional unit of the kidney is known as the nephron. It aids in the removal of waste and surplus...
21. Choose the correct statement that describes arteries.
(a) They have thick elastic walls, blood flows under high pressure; collect blood from different organs and bring it back to the heart (b) They have thin walls with valves inside, blood flows under...
20. In which of the following vertebrate group/groups, the heart does not pump oxygenated blood to different parts of the body?
(a) Pisces and amphibians (b) Amphibians and reptiles (c) Amphibians only (d) Pisces only The answer is (d) Pisces only Explanation: This is due to the heart's solitary circulation, which pumps...
19. Single circulation i.e., blood flows through the heart only once during one cycle of passage through the body, is exhibited by
(a) Labeo, Chameleon, Salamander (b) Hippocampus, Exocoetus, Anabas (c) Hyla, Rana, Draco (d) Whale, Dolphin, Turtle The answer is (b) Hippocampus, Exocoetus, Anabas Explanation: Option a)...
18. What prevents backflow of blood inside the heart during contraction?
(a) Valves in heart (b) Thick muscular walls of ventricles (c) Thin walls of atria (d) All of the above The answer is (a) Valves in the heart Explanation: The walls of the heart are only responsible...
17. Which of the following statement (s) is (are) true about the heart?
(i) The left atrium receives oxygenated blood from different parts of the body while the right atrium receives deoxygenated blood from lungs (ii) Left ventricle pumps oxygenated blood to different...
16. During respiration exchange of gases take place in
16. During respiration exchange of gases take place in (a) trachea and larynx (b) alveoli of lungs (c) alveoli and throat (d) throat and larynx The answer is (b) alveoli of lungs Explanation: The...
15. Which is the correct sequence of air passage during inhalation?
(a) Nostrils →larynx →pharynx →trachea →lungs (b) Nasal passage →trachea →pharynx →larynx →alveoli (c) larynx →nostrils →pharynx →lungs (d) Nostrils →pharynx →larynx →trachea →alveoli The answer is...
Which of the following statement(s) is (are) true about respiration?
(i) During inhalation, ribs move inward and diaphragm is raised (ii) In the alveoli, exchange of gases takes place i.e., oxygen from alveolar air diffuses into blood and carbon dioxide from the...
13. Which of the following is most appropriate for aerobic respiration?
Answer is Option (B)
12. The correct sequence of anaerobic reactions in yeast is
The answer is d) Explanation: Glucose is broken down in the cytoplasm of yeast in anaerobic conditions to create Pyruvate, which is then broken down further to Ethanol and carbon dioxide.
11. When air is blown from the mouth into a test-tube containing lime water, the lime water turned milky due to the presence of
(a) oxygen (b) carbon dioxide (c) nitrogen (d) water vapour The answer is (b) carbon dioxide Explanation: When carbon dioxide combines with lime water, the lime water becomes milky
10. Choose the function of the pancreatic juice from the following
(a) trypsin digests proteins and lipase carbohydrates (b) trypsin digests emulsified fats and lipase proteins (c) trypsin and lipase digest fats (d) trypsin digests proteins and lipase emulsified...
9. In which part of the alimentary canal food is finally digested?
(a) Stomach (b) Mouth cavity (c) Large intestine (d) Small intestine The answer is (d) Small intestine Explanation: Although the primary digestive process happens in the mouth and stomach, the...
8. A few drops of iodine solution were added to rice water. The solution turned blue-black in colour. This indicates that rice water contains
(a) complex proteins (b) simple proteins (c) fats (d) starch The answer is (d) starch Explanation Amylose and Amylopectin are the two components of starch. Amylose interacts with iodine to generate...
25. Why are crop fields known as artificial ecosystems?
Solution – crop fields are artificial ecosystem as the plants in these fields are grown by the man . They are grown in confirmation to the weather , type of soil , land and market requirement . They...
7. Which part of alimentary canal receives bile from the liver?
(a) Stomach (b) Small intestine (c) Large intestine (d) Oesophagus The answer is (b) Small intestine Explanation: The hepta pancreatic duct transports bile from the gall bladder to the small...
24. What are the advantages of cloth bags over plastic bags during shopping?
Solution - the advantages of cloth bags over plastic bags during shopping are : They can be re – usedThey are bio degradableThey are cost effective as can be used many timesEnvironmental friendlyNo...
6. The inner lining of the stomach is protected by one of the following from hydrochloric acid. Choose the correct one (a) Pepsin
(b) Mucus (c) Salivary amylase (d) Bile The answer is (b) Mucus
5. If salivary amylase is lacking in the saliva, which of the following events in the mouth cavity will be affected?
(a) Proteins breaking down into amino acids (b) Starch breaking down into sugars (c) Fats breaking down into fatty acids and glycerol (d) Absorption of vitamins The answer is (b) Starch breaking...
23. Write the common food chain of a pond ecosystem.
Solution – a food chain begins with a producer .The most common food chain of a pond ecosystem is as follows : Phyto planktons ↓ Small aquatic animals ( like larvae, shrimps, Insects etc. ) ↓ Fish ↓...
4. Which is the correct sequence of parts in the human alimentary canal?
(a) Mouth → stomach → small intestine → oesophagus → large intestine (b) Mouth →oesophagus → stomach → large intestine → small intestine (c) Mouth → stomach → oesophagus → small intestine → large...
3. Select the correct statement
(a) Heterotrophs do not synthesise their own food (b) Heterotrophs utilise solar energy for photosynthesis (c) Heterotrophs synthesise their own food (d) Heterotrophs are capable of converting...
22. Why is improper disposal of waste a curse to the environment?
Solution – improper disposal of waste is a curse to environment . It is so because it pollutes our environment ( which includes air , water and soil ) . This results in harmful effects on the human...
2. In which of the following groups of organisms, food material is broken down outside the body and absorbed?
(a) Mushroom, green plants, Amoeba (b) Yeast, mushroom, bread mould (c) Paramecium, Amoeba, Cuscuta (d) Cuscuta, lice, tapeworm The answer is (b) Yeast, mushroom, bread mould Explanation:...
21. Disposable plastic plates should not be used because
(a) they are made of materials with lightweight (b) they are made of toxic materials (c) they are made of biodegradable materials (d) they are made of non-biodegradable materials Correct option – (...
20. If a grasshopper is eaten by a frog, then the energy transfer will be from
(a) producer to decomposer (b) producer to primary consumer (c) primary consumer to secondary consumer (d) secondary consumer to primary consumer Correct option – ( c ) Explanation for correct...
1. Which of the following statements about the autotrophs is incorrect?
(a) They synthesise carbohydrates from carbon dioxide and water in the presence of sunlight and chlorophyll (b) They store carbohydrates in the form of starch (c) They convert carbon dioxide and...
19. The decomposers in an ecosystem
(a) convert inorganic material, to simpler forms (b) convert organic material to inorganic forms (c) convert inorganic materials into organic compounds (d) do not breakdown organic compounds Correct...
18. What will happen if deer is missing in the food chain given below? Grass → Deer → Tiger
(a) The population of tiger increases (b) The population of grass decreases (c) Tiger will start eating grass (d) The population of tiger decreases and the population of grass increases Correct...
17. In the given Figure 15.1 the various trophic levels are shown in a pyramid. At which trophic level is maximum energy available?
(a) T4 (b) T2 (c) T1 (d) T3 Correct option – ( T1 ) Explanation for correct option – the maximum energy will be available at the trophic level T1 . For producers maximum amount of energy is...
16. The percentage of solar radiation absorbed by all the green plants for the process of photosynthesis is about
(a) 1 % (b) 5 % (c) 8 % (d) 10 % Correct option – ( a ) Explanation for correct option – plants prepare there food in the presence of sunlight and chlorophyll and water . Photosynthetically active...
15. Which group of organisms are not constituents of a food chain?
(i) Grass, lion, rabbit, wolf (ii) Plankton, man, fish, grasshopper (iii) Wolf, grass, snake, tiger (iv) Frog, snake, eagle, grass, grasshopper (a) (i) and (iii) (b) (iii) and (iv) (c) (ii) and...
14. Which of the statement is incorrect?
(a) All green plants and blue-green algae are producers (b) Green plants get their food from organic compounds (c) Producers prepare their own food from inorganic compounds (d) Plants convert solar...
13. Which of the following limits the number of trophic levels in a food chain?
(a) Decrease in energy at higher trophic levels (b) Sufficient food supply (c) Polluted air (d) Water Correct option –( a ) Explanation for correct answer – at a particular trophic level the...
12. In the following groups of materials, which group (s) contains only non-biodegradable items?
(i) Wood, paper, leather (ii) Polythene, detergent, PVC (iii) Plastic, detergent, grass (iv) Plastic, bakelite, DDT (a) (iii) (b) (iv) (c) (i) and (iii) (d) (ii) and (iv) Correct option – ( d )...
11. Excessive exposure of humans to U V-rays results in
(i) damage to the immune system (ii) damage to lungs (iii) skin cancer (iv) peptic ulcers (a) (i) and (ii) (b) (ii) and (iv) (c) (i) and (iii) (d) (iii) and (iv) Correct option – ( c ) Explanation...
10. Flow of energy in an ecosystem is always
(a) unidirectional (b) bidirectional (c) multidirectional (d) no specific direction Correct option – ( a ) Explanation for correct option – the flow of energy in an ecosystem is always in one...
9. Organisms of a higher trophic level which feed on several types of organisms belonging to a lower trophic level constitute the
(a) food web (b) ecological pyramid (c) ecosystem (d) food chain Correct option – ( a ) Explanation for correct option – food web is composed of organisms of higher trophic level which eat several...
8. In an ecosystem, the 10% of energy available for transfer from one trophic level to the next is in the form of
(a) heat energy (b) light energy (c) chemical energy (d) mechanical energy Correct option – ( c ) Explanation for correct option – energy that is transmitted from one trophic level to another one is...
7. Organisms which synthesise carbohydrates from inorganic compounds using radiant energy are called
(a) decomposers (b) producers (c) herbivores (d) carnivores Correct option – ( b ) Explanation for correct option – producers are those which produce their own food with the help of solar energy ,...
6. Depletion of ozone is mainly due to
(a) chlorofluorocarbon compounds (b) carbon monoxide (c) methane (d) pesticides Correct option – ( a ) Explanation for correct option - in the stratosphere chlorofluorocarbon compounds are...
5. Accumulation of non-biodegradable pesticides in the food chain in increasing amount at each higher trophic level is known as
(a) eutrophication (b) pollution (c) biomagnification (d) accumulation Correct option – ( c ) Explanation for correct option – biomagnification refers to the rise in concentration of adverese...
4. In the given food chain, suppose the amount of energy at the fourth trophic level is 5 kJ, what will be the energy available at the producer level?
Grass → Grasshopper → Frog → Snake → Hawk (a) 5 k J (b) 50 k J (c) 500 k J (d) 5000 k J Correct option – ( d ) Explanation for correct option – at a particular trophic level the available energy...
3. An ecosystem includes
(a) all living organisms (b) non-living objects (c) both living organisms and non-living objects (d) sometimes living organisms and sometimes non-living objects Correct option – ( c ) Explanation...
2. In a food chain, the third trophic level is always occupied by
(a) carnivores (b) herbivores (c) decomposers (d) producers Correct option – ( a ) Explanation for correct option – carnivores are placed at the third place in the trophic level . Explanation for...
1. Which one of the following is an artificial ecosystem?
(a) Pond (b) Crop field (c) Lake (d) Forest Correct option – ( b ) Explanation for correct option – crop field is artificial ecosystem . It is an area in which plants are grown selectively ....
Characters that are transmitted from parents to offspring during reproduction show
(a) only similarities with parents
(b) only variations with parents
(c) both similarities and variations with parents
(d) neither similarities nor variations
Solution: Reproduction has two modes- sexual and asexual. In the sexual mode of reproduction two parents are involved in the fertilization process leading to the formation of a single-celled zygote....
Characters transmitted from parents to offspring are present in
(a) cytoplasm
(b) ribosome
(c) Golgi bodies
(d) genes
Solution: Characters are transmitted from parents to offspring via genes. Genes are the smallest unit of heredity which contain genetic information, and they encode for a particular character,...
Offspring formed by the asexual method of reproduction have greater similarity among themselves because
(i) asexual reproduction involves only one parent
(ii) asexual reproduction does not involve gametes
(iii) asexual reproduction occurs before sexual reproduction
(iv) asexual reproduction occurs after sexual reproduction
(a) (i) and (ii)
(b) (i) and (iii)
(c) (ii) and (iv)
(d) (iii) and (iv)
<br>(i) asexual reproduction involves only one parent</br> <br> (ii) asexual reproduction does not involve gametes </br> <br> (iii) asexual reproduction occurs before sexual...
Which of the following is the correct sequence of events of sexual reproduction in a flower?
(a) pollination, fertilization, seedling, embryo
(b) seedling, embryo, fertilization, pollination
(c) pollination, fertilization, embryo, seedling
(d) embryo, seedling, pollination, fertilization
Solution: 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,...
In a flower, the parts that produce male and female gametes (germ cells) are
(a) stamen and anther
(b) filament and stigma
(c) anther and ovary
(d) stamen and style
Solution: In angiosperms, the male reproductive part is known as the stamen and the female reproductive part is known as the stigma. The stamen has a head that is called the anther responsible for...
In the list of organisms given below, those that reproduce by the asexual method are
(i) banana
(ii) dog
(iii) yeast
(iv) Amoeba
(a)(ii) and (iv)
(b)(i), (iii) and (iv)
(c)(i) and (iv)
(d)(ii), (iii) and (iv)
Solution: Reproduction in organisms is a method of producing new offspring which have the same characteristics as the parent. The reproduction in bananas occurs by parthenogenesis which is an...
53. Why is the flow of signals in a synapse from axonal end of one neuron to dendritic end of another neuron but not the reverse?
Solution - travelling of the electrical impulses takes place in the neurons . When it is transmitted to another neuron it takes the form of the neurotransmitter . Neurotransmitter are...
52. How does chemical coordination take place in animals?
Solution - with the help of the hormones the chemical coordination in the animals takes place . Hormones are secreted by the glands present in the endocrine system . The growth and development of...
51. “Nervous and hormonal systems together perform the function of control and coordination in human beings.” Justify the statement.
Solution : the function of control and coordination is regulated by the hormonal and nervous system . All the organs and organ system in the body are under the control of the brain . Brain controls...
50. What are reflex actions? Give two examples. Explain a reflex arc .
Solution – reflex action is a rapid and involuntary response to a stimulus . Examples of reflex action are – in bright light the pupil of the changes in size . ...
49. Name various plant hormones. Also give their physiological effects on plant growth and development.
Solution – some of the plant hormones are gibberellin – it is responsible for the growth of the stemauxin – it causes the cell to elongateabscisic acid – the growth of the plant is halted and...
48. Mention one function for each of these hormones :
(a) Thyroxin (b) Insulin (c) Adrenaline (d) Growth hormone (e) Testosterone. Solution – (a) Thyroxin : it is important in the role of digestion , heart and muscle function , development of brain and...
47. What constitutes the central and peripheral nervous systems? How are the components of the central nervous system protected?
Solution – Brain and spinal cord makes up the central nervous system . peripheral nervous system comprises of nerves which are present outside the spinal cord . Central nervous system is very well...
46. What are the major parts of the brain? Mention the functions of different parts.
Solution – major parts of the brain along with their functions are – forebrain - it has an important role in information processing , sensory and associative functions and voluntary motor...
45. Draw the structure of a neuron and explain its function.
Solution - neurons transmit information among the different areas of the brain and rest of the nervous system . Structure of the neuron – Cell body have dendrites which are responsible to receives...
44. Answer the following :
(a) Name the endocrine gland associated with brain? (b) Which gland secretes digestive enzymes as well as hormones? (c) Name the endocrine gland associated with kidneys? (d) Which endocrine gland is...
43. Answer the following :
(b) Dwarfism results due to deficiency of which hormone? (a) Which hormone is responsible for the changes noticed in females at puberty? (c) Blood sugar level rises due to deficiency of which...
42. What happens at the synapse between two neurons?
Solution – electrical impulse releases chemicals at the end of the axon . These chemicals cross the synapse and in the dendrite similar electrical impulses are created .
41. What will happen if the intake of iodine in our diet is low ?
Solution – our metabolism is controlled by thyroid hormone . Low levels of iodine results in low thyroid function and also causes abnormal enlargement of the thyroid gland ( hypothyroidism ) known...
40. What is a tropic movement? Explain with an example .
Solution – when a plant shows some growth movement in response to a stimulus then it is known at tropic movement . Movement can be either direction that is it can be towards the stimulus or away...
39. Match the terms of Column (A) with those of Column (B)
Column AColumn B(a) Olfactory receptors(i) Tongue(b) Thermo receptors (temperature receptors)(ii) Eye(c) Gustatoreceptors(iii) Nose(d) Photoreceptors(iv) Skin solution Column AColumn B(a) Olfactory...
38. Label the parts of a neuron in Figure 7.5.
Figure Solution – DendriteCell bodyAxonAxon terminal
37. In Figure 7.4 (a), (b) and (c), which appears more accurate and why?
Figure Solution – figure ( a ) is more accurate . It is so because the plant is showing the ideal condition that is the roots are showing positive geotrophism and the shoot system is showing...
36. Label the endocrine glands in Figure 7.3.
figure Solution – Pineal glandPituitary glandThyroid glandThymus
35. Name the plant hormones responsible for the following
(a) elongation of cells (b) growth of stem (c) promotion of cell division (d) falling of senescent leaves. Solution – (a) elongation of cells – Auxin (b) growth of stem – gibberellin (c) promotion...
34. Label the parts (a), (b), (c) and (d) and show the direction of flow of electrical signals in Figure 7.2.
Solution – Sensory neuron Spinal cord Motor neuron Muscle Flow of electrical signals: Receptors in hand ==> Sensory neurons ==. Spinal cord (CNS) ==>Motor neurons ==> Effector - muscles in...
33. In humans, the life processes are controlled and regulated by
(a) reproductive and endocrine systems (b) respiratory and nervous systems (c) endocrine and digestive systems (d) nervous and endocrine systems Correct option – ( d ) Explanation for correct option...
32. The junction between two neurons is called
(a) cell junction (b) neuromuscular junction (c) neural joint (d) synapse Correct option – ( d ) Explanation for correct option – synapse is a structure present in nervous system which allows a...
31. Which of the following endocrine glands is unpaired?
(a) Adrenal (b) Testes (c) Pituitary (d) Ovary Correct option – ( c ) Explanation for correct option – Pituitary is the only gland which is unpaired that is there ios only one pituitary gland in...
30. The hormone which increases the fertility in males is called
(a) oestrogen (b) testosterone (c) insulin (d) growth hormone Correct option – ( b ) Explanation for correct option – Testosterone is the male sex hormone produces in testes of males which promotes...
29. A doctor advised a person to take an injection of insulin because
(a) his blood pressure was low (b) his heart was beating slowly (c) he was suffering from goitre (d) his sugar level in blood was high Correct option – ( d ) Explanation for correct option –...