$(a)$ Draw a sectional view of the human heart and label on it Aorta,Pulmonary arteries,Vena cava,Left ventricle.
$(b)$ Why is double circulation of blood necessary in human beings?

During the respiration of an organism $A$,one molecule of glucose produces two $ATP$ molecules,whereas in the respiration of another organism $B$,one molecule of glucose produces $38$ $ATP$ molecules.
$(a)$ Which organism is undergoing aerobic respiration?
$(b)$ Which organism is undergoing anaerobic respiration?
$(c)$ Which type of organism,$A$ or $B$,can convert glucose into alcohol?
$(d)$ Name one organism which behaves like $A$.
$(e)$ Name two organisms which behave like $B$.

Why is the rate of breathing in aquatic organisms much faster than that seen in terrestrial organisms?

Choose the function of the pancreatic juice from the following:

State two functions of stomata.

Which of the following is an incorrect statement?