Write the important roles of the following :

(a) Rectum

(b) Gastric juice

(c) Epiglottis

(d) Small intestine

(e) Tongue

Give reasons/explain :

(a) Only animals require a digestive system and not plants.

(b) There are no enzymes to digest vitamins.

(c) Thorough chewing of food in mouth is helpful in digestion.

(d) Bile juice does not contain any enzyme but is still important in digestion.

(e) The inner layer of small intestine has a large number of finger-like projections called villi.

Mention two ways in which the ileum of a mammal is adapted for the absorption of digested food.

The stomach secretes gastric juice, which contains hydrochloric acid. What is its function?