Name the following with reference to the alimentary canal:
$(a)$ $(i)$ The largest gland.
$(ii)$ The gland that secretes digestive enzymes as well as hormones.
$(iii)$ The part where digested food is absorbed.
$(b)$ What are villi? Mention their function.

Match Group $(A)$ with Group $(B)$:

Group $(A)$	Group $(B)$
$(a)$ Autotrophic nutrition	$(i)$ Leech
$(b)$ Heterotrophic nutrition	$(ii)$ Paramecium
$(c)$ Parasitic nutrition	$(iii)$ Deer
$(d)$ Digestion in food vacuoles	$(iv)$ Green plant

Explain the role of the mouth in the digestion of food.

State two functions of stomata.

$(a)$ State the reason for the following:
$(i)$ Herbivores need a longer small intestine,while carnivores have a shorter small intestine.
$(ii)$ The lungs in human beings are designed to maximize the area for the exchange of gases.
$(b)$ The rate of breathing in aquatic organisms is much faster than that seen in terrestrial organisms.

What is the main toxic waste that the kidneys filter from the blood?