a. Open circulatory system and closed circulatory system

b. Oviparous and viviparous characteristic

c. Direct development and Indirect development

a) Open circulatory system

●Blood is pumped out the heart ●the cells and tissues are directly bathed in the open circulatory system 

Closed circulatory system 

● Blood is pumped inside  the heart.

●The closed circulatory system is circulated throughout the body with the help of a series of vessels.

b) Animals that lay fertilized and unfertilized eggs  in the environment are known as oviparous on the other hand those who are  giving birth to young ones are viviparous.

c) When a larval stage is absent in the development of the organism, it is said to be direct development  on the other hand the larval stage is present in the development of the organism which does not resemble the adult is said to be  indirect development.