1.    Fill in the blanks:

(a) The main steps of digestion in humans are ingestion, digestion, absorption, assimilation and egestion.

(b) The largest gland in the human body is liver.

(c) The stomach releases hydrochloric acid and gastric juice which act on food.

(d) The inner wall of the small intestine has many finger-like outgrowths called villi.

(e) Amoeba digests its food in the food vacuole.

2.    (a) F

(b) T

(c) T

(d) T

3.    (a) (iii) small intestine.

(b) (iv) large intestine.

4.   Food components      product of digestion

Carbohydrates                 Sugar

Protein                              Amino Acids

Fats                                    Fatty acids and glycerol

5.    The inner wall of the small intestine have thousands of finger-like outgrowths. These are called villi. Villi are located in the small intestine. The villi increase the surface area for absorption of the digested food. Each villus has a network of thin and small blood vessels close to its surface. The surface of the villi absorbs the digested food materials.

6.    Bile is produced by liver and is stored in gall bladder. Bile juice digests fat.

7.    Cellulose can be digested by ruminants but not by human beings. The human being do not produce cellulose digesting enzyme.

8.    Cellulose is a type of carbohydrate that can be digested by ruminants but not by humans. Ruminants have a large sac-like structure called rumen which is present in between the small intestine and large intestine. The cellulose is digested here by the action of certain bacteria which are not present in humans.

9.    Glucose is the simplest form of carbohydrate which can be broken easily to give energy. So, glucose is called instant energizer.

(i) small intestine

(ii) buccal cavity

(iii) stomach

(iv) small intestine

(v) large intestine

11.  Similarity: Both amoeba and human use digestive juices to digest food.

Difference: Human needs to chew food, whereas in amoeba, there is no chewing.

12.  (a) (iii)

(b) (iv)

13.  

14.  No, because to live alive a healthy life we need a complete balance of all nutrients. Raw green vegetables may have cellulose which cannot be digested by us. So, only green leafy vegetables will not solve the purpose.