Question

Which of the following breaks the food into the simpler form that the body can use?
A. Digestive juice
B. Teeth
C. Water
D. None of the above

Answer 1

Digestion is the process in which complex substances that are present in our food are broken down to form simpler ones so that it can be easily absorbed by the body. During digestion, the food passes through the alimentary canal. The main parts of the alimentary canal are- mouth, oral cavity, oesophagus, stomach, pancreas, small intestine, large intestine and rectum.

Complete answer
From mouth to the intestine, different parts of the alimentary canal help in the digestion process. The teeth are present in the oral cavity that helps in mastication and grinding of food in the presence of saliva. The masticated food particles are then conveyed into the oesophagus through pharynx in the form of bolus by swallowing.
The Salivary gland, gastric glands and pancreas and liver mainly helps in the digestion process. These glands secrete various juices that help in breakdown of different substances of food. As they help in digestion of food, they are called digestive juices.
The salivary glands are present in the mouth secretes saliva in which salivary amylase is present. This salivary amylase helps in the breakdown of carbohydrates into the maltose. In the stomach, gastric glands are present which helps in the breakdown of proteins. The pepsinogen proenzyme is converted into the enzyme pepsin in the presence of HCl. The pepsin enzyme helps in the breakdown of proteins into proteoses and peptones.
Bile juice is secreted from the liver which helps in the breakdown of fats.
The pancreatic juice from the pancreas contains various enzymes such as trypsinogen, chymotrypsinogen, amylases, lipases etc. which helps in the breakdown of different substances of food. These enzymes get activated by the trypsinogen which in turn is activated by the enterokinase enzyme secreted from intestinal mucosa.
The various enzymes from intestinal juice finally act on the partially simpler products and convert it into simpler absorbable forms.
Water is the form in which most of the substances can be dissolved. It is present in all the cells, tissues and organs and performs different functions of the body. It helps in the regulation of temperature of the cells.

Thus the answer to the above question is option (A) digestive juice as it contains enzymes which help in the conversion of complex substances into simpler forms.

Note: Rennin is a proteolytic enzyme which is present in the stomach of mammals. It is produced from the chief or peptic cells of the stomach. It is very important for the digestion of milk in young ones. With age, the secretion of rennin is decreased and it is replaced by pepsin enzymes.