Human Digestive System

This is the correct answer option as all the given statements are correct.

This is the correct answer as both statements 'b' and 'c' are incorrect. Undigested food is stored in rectum. Undigested solid food is egested from the body through the anus.

This is the correct answer. During the process of respiration, food is oxidised in mitochondria of the cells to release energy.

It prevents food from going into the trachea by closing it during swallowing.

Gastric juice contain HCl along with certain protein digesting enzymes and mucous.

The opening of the esophagus into the cardiac stomach is guarded by the cardiac sphincter, which prevents regurgitation of food.

These are not a part of the alimentary canal, they help in digestion by providing their own enzymes.

Gastrin is a hormone secreted by the pyloric stomach. It stimulates secretion of gastric juices by the parietal cells of stomach.

The main function of intestinal villi is the absorption of food. It helps in digestion by increasing the surface area of the intestine. #

The first and the second chamber of the ruminant stomach, the rumen and reticulum contain several cellulose digesting bacteria.

The large intestine has a worm like blind tube called the vermiform appendix, which is regarded as a vestigial in humans. An inflammation and infection of the appendix is called appendicitis.

The involuntary muscle movement of the alimentary canal is called peristalsis.

These are large cells which secrete diluted HCl and intrinsic factor. These are also called parietal cells.

Retroperistalsis is the reverse peristaltic movement that allows ruminants to regurgitate cud from the rumen back to the mouth for rechewing. Peristalsis moves food forward, while retroperistalsis enables the characteristic leisurely remastication of stomach contents that defines ruminant digestion.

In ruminants, the rumen is the primary site for absorption of fluid food and volatile fatty acids produced during fermentation. While the reticulum, omasum, and abomasum have specialized functions, the rumen's vast surface area and vascularization make it the principal absorptive organ for fluid nutrients.