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प्रश्न
What is digestion? Why do only animals require a digestive system?
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उत्तर
Digestion is the process of breaking down complex food materials into simpler substances by the action of enzymes.
Need for a digestive system:
(i) Large complex molecules like carbohydrates, proteins and lipids need to be broken down to simpler molecules. These simpler molecules can then be absorbed and utilized by the body.
(ii) The breaking down of complex food molecules into their simpler form is possible only through the process of digestion.
(iii) During digestion, large complex macromolecules present in food are converted into small simpler molecules, which can be simplified in different compartments of digestive system only.
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संबंधित प्रश्न
The gall bladder temporarily stores bile.
When a person puts food in his mouth, then teeth cut it into small pieces, chew and grind it. The glands A in the mouth secrete a substance B which is mixed with the food by tongue. The substance B contains an enzyme C which starts the digestion of food in the mouth. The slightly digested food from the mouth goes down a tube D. The special type of movements E in the walls of tube D push the food into stomach for further digestion. The stomach wall secretes gastric juice containing three substance F, G and H. One of the functions of F is to kill bacteria which may enter the stomach with food. The substance G protects the inside layer of stomach from the damaging effect of substance F whereas substance H is and enzyme for digestion. The partially digested food then enters into small intestine for further digestion.
(a) What is (i) gland A (ii) substance B, and (iii) enzyme C?
(b) Name the tube D.
(c) What is the movement E known as?
(d) What are (i) F (ii) G, and (iii) H?
Define the terms 'nutrients'.
Why is there no enzyme to digest vitamins?
Why is the small intestine the most important organ of the digestive system?
Define the term nutrition.
Write true or false for the below statement. Rewrite the false statements correctly.
The wave-like motion of stomach muscles to push the food is called peristalsis.
The question has four options. Choose the correct answer:
The hardest constituent of the tooth is
The process by which the body removes waste is called ______.
In which part of the alimentary canal food is finally digested?
