CBSE Class 10 Science 2020 · Paper 31/4/1 · Question 27

(a) Nutrition is necessary because food provides energy for the various metabolic processes of the body, and supplies materials for the formation of new cells (growth) and the repair of damaged or worn-out cells and tissues; it also helps the body develop resistance against diseases. (b) Peristalsis: the rhythmic contraction and relaxation of the muscles in the lining of the alimentary canal pushes the food forward. (c) Herbivores eat plant material rich in cellulose, which takes longer to digest, so they need a longer small intestine; carnivores eat meat, which is easier to digest, so their small intestine is shorter. (d) The inner lining of the stomach would not be protected from the hydrochloric acid, so the acid would damage (erode) the stomach wall, which can lead to ulcers.