Formative Practice 9.4 (Form 4 Biology Textbook Exercise and Answer)

Question 1:
State the main function of the large intestine.

The main functions of the large intestine are water and vitamin reabsorption, and faeces formation.

Question 2:
What are the substances absorbed in the large intestine?

Water, minerals, the metabolic by-products of bacteria such as vitamin B, K and folic acid.

Question 3:
Explain the importance of water absorption and vitamins in the large intestine.

The significance of water and vitamin absorption:
• The absorption of water in the large intestine helps to form semi-solid faeces. This process enables the body to retain water.

• The absorption of vitamins maintains health.

Question 4:
Explain the formation process of faeces.

Formation of faeces:
• After the absorption of nutrients in the small intestine, the remaining mixture enters the colon.

• The remainder mixture consists of water, undigested food, bacteria, dead cells and cellulose.

• The movement of undigested food is facilitated by peristalsis.

• In the colon, the absorption of mineral salts and water takes place until faeces are formed.

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