NCERT Exemplar Solutions Class 7 Science Nutrition in Animals

Multiple Choice Questions

Question 1:  Given below from (i) to (iv) are some food items.

1. Boiled and mashed potato
2. Glucose solution
3. A slice of bread
4. Mustard oil

Which of the above will give blue-black colour when tested with iodine?

(a) (i) and (ii)

(b) (i) and (iii)

(c) (ii) and (iii)

(d) (iii) and (iv) 

Solution 1:  (b) (i) and (iii) 

There is abundance of starch in mashed potatoes and bread so on tested with iodine it gives blue-black colour.

Question 2:  Which of the following pair of teeth differ in structure but are similar in function?

(a) canines and incisors.

(b) molars and premolars.

(c) incisors and molars.

(d) premolars and canines. 

Solution 2:  (b) Molars and premolars

Molars are the largest teeth in the mouth. They grind, tear and crush the food. Premolars are different in structure from molar as they have flat biting surface. But the functions of premolar teeth are same as molars.

Question 3:  Read carefully the terms given below. Which of the following set is the correct combination of organs that do not carry out any digestive functions?

(a) Oesophagus, Large Intestine, Rectum

(b) Buccal cavity, Oesophagus, Rectum

(c) Buccal cavity, Oesophagus, Large Intestine

(d) Small Intestine, Large Intestine, Rectum 

Solution 3:  (a) Oesophagus, Large Intestine, Rectum

Oesophagus is the food pipe from where the food pushes downwards to the organs of alimentary canal. The purpose of large intestine is to absorb water and salt from the material that has not been digested. The last portion of large intestine is rectum. It is temporary storehouse spot for faeces. 

Question 4:  The swallowed food moves downwards in the alimentary canal because of

(a) force provided by the muscular tongue.

(b) the flow of water taken with the food.

(c) gravitational pull.

(d) the contraction of muscles in the wall of the food pipe. 

Solution 4:  (d) the contraction of muscles in the wall of the food pipe. 

There are muscles in the wall of food pipe which induces the food to move downward. The muscles of oesophagus do continuous contraction while pushing food downwards.

Question 5:  The acid present in the stomach

(a) kills the harmful bacteria that may enter along with the food.

(b) protects the stomach lining from harmful substances.

(c) digests starch into simpler sugars.

(d) makes the medium alkaline. 

Solution 5:  (a) kills the harmful bacteria that may enter along with the food. 

The acid which is secreted by the walls of stomach is Hydrochloric Acid which destroys the harmful bacteria that may enter along with the food.

Question 6:  The finger-like outgrowths of Amoeba help to ingest food. However, the finger-like outgrowths of human intestine help to

(a) digest the fatty food substances.

(b) make the food soluble.

(c) absorb the digested food.

(d) absorb undigested food. 

Solution 6:  (c) absorb the digested food.

The fingers like projections are Villi which are present in the small intestine of the body. These finger-like outgrowths helps the small intestine to absorb digested food.

Question 7:  Read the following statements with reference to the villi of the small intestine.

(i) They have very thin walls.

(ii) They have a network of thin and small blood vessels close to the surface.

(iii) They have small pores through which food can easily pass.

(iv) They are finger-like projections which enable the villi to absorb digested food.

Identify those statements which are correct.

(a) (i), (ii) and (iv)

(b) (ii), (iii) and (iv)

(c) (iii) and (iv)

(d) (i) and (iv) 

Solution 7:  (a) (i), (ii) and (iv)

Villi of the small intestine do not have small pores through which food can pass easily. Infact villi which are present in small intestine are thousand in number having very thin walls. Villi absorb nutrients from the food we eat and then transfer those nutrients into the bloodstream that is why they have network of thin and small blood vessels lose to the surface.

Question 8:  The false feet of Amoeba is used for

(a) movement only.

(b) the capture of food only.

(c) the capture of food and movement.

(d) exchange of gases only. 

Solution 8:  (c) capture of food and movement.

Amoeba is single celled organism which does not have any fixed shape. It kept on changing its shape according to its need which is usually in the form of movement and intake of food. The false feet look finger-like projection known as pseudopodia.

Question 9:   The enzymes present in the saliva convert

(a) fats into fatty acids and glycerol.

(b) starch into simple sugars.

(c) proteins into amino acids.

(d) complex sugars into simple sugars. 

Solution 9:  (b) starch into simple sugars. 

Salivary amylase enzyme is present in the saliva of mouth. This saliva breaks starch into simple sugars. The broken starch is in the form of simple sugar then digested by enzymes in the stomach and small intestine.

Question 10:  Cud is the name given to the food of ruminants which is

(a) swallowed and undigested.

(b) swallowed and partially digested.

(c) properly chewed and partially digested.

(d) properly chewed and completely digested. 

Solution 10:  (b) swallowed and partially digested.

Ruminants have four compartments in the stomach. Of the four compartments the rumen is the largest section and main digestive centre. The food gets partially digested and stored in the rumen is called cud. Whenever ruminant wish to chew the cud, he can bring the cud back to the mouth in small lumps and chew it.

Question 11:  Choose the correct order of terms that describes the process of nutrition in ruminants.

(a) swallowing → partial digestion → chewing of cud → complete digestion

(b) chewing of cud → swallowing → partial digestion → complete digestion

(c) chewing of cud → swallowing → mixing with digestive juices → digestion

(d) swallowing → chewing and mixing → partial digestion → complete digestion 

Solution 11:  (a) swallowing → partial digestion → chewing of cud → complete digestion

The process of nutrition in ruminants goes from swallowing to partial digestion to chewing of cud to complete digestion.

Question 12:  Cellulose-rich food substances are a good source of roughage in human beings because

(a) human beings do not have cellulose-digesting enzymes.

(b) cellulose gets absorbed in the human blood and converts into fibres.

(c) the cellulose-digesting bacteria convert cellulose into fibres.

(d) cellulose breaks down into smaller components which are egested as roughage. 

Solution 12:  (a) human beings do not have cellulose-digesting enzymes.

Human body lacks cellulose-digesting enzymes. Cellulose rich food substances are excellent source of roughage in human beings.

Very Short Answer Questions..................

Question 13:  Name the parts of the alimentary canal where

(i) water gets absorbed from undigested food.

(ii) digested food gets absorbed.

(iii) taste of the food is perceived.

(iv) bile juice is produced. 

Solution 13:

(i) Water gets absorbed from undigested food in large intestine.

(ii) Digested food gets absorbed in small intestine.

(iii) Taste of the food is perceived in tongue.

(iv) Bile juice is prepared in Liver.

Question 14:  Mark the following statements as True or False. If false, write the correct statements.

(a) Tongue is attached to the roof of the mouth cavity at the back.

(b) The large intestine is longer and wider than the small intestine of the human alimentary canal.

(c) Mucus protects the stomach lining from damage.

(d) All heterotrophs have a similar basic process of nutrition. 

Solution 14:

1. False- Tongue in not attached with the roof of the mouth but it is attached with the floor of the mouth cavity.
2. False- In the alimentary canal large intestine is the shorter and wider than the small intestine.
3. True
4. True

Question 15:  Choose the odd one out from each group and give reasons.

(i) liver, salivary gland, starch, gall bladder

(ii) stomach, liver, pancreas, salivary gland

(iii) tongue, absorption, taste, swallow

(iv) oesophagus, small intestine, large intestine, rectum 

Solution 15:

1. The odd one out from liver, salivary gland, starch, gall bladder is starch as it is a type of carbohydrate and liver, salivary gland and gall bladder are glands.
2. The odd one out from stomach, liver, pancreas, salivary gland is stomach as it is a muscular organ but liver, pancreas, salivary gland are digestive glands.
3. The odd one out from tongue, absorption, taste, swallow is absorption is not related with buccal cavity and tongue, taste, swallow are related with buccal cavity.
4. The odd one out from oesophagus, small intestine, large intestine, rectum is small intestine as it is a part of digestion process but oesophagus, large intestine and rectum are not parts of digestion process.

Question 16:   You were blindfolded and asked to identify the drinks provided in two different glasses. You could identify drink A as lime juice and B as bitter gourd juice. How could you do it in spite of being blindfolded? 

Solution 16:   In case of blindfolded we can trace the juices by tasting the juices with the help of taste buds which are there in the tongue.

 

Question 17:  Fill in the blanks with suitable words:

(a) The alimentary canal stretches from ............. to ................

(b) Teeth are rooted in separate ................ in between the ...................

(c) Digestion of food starts in ............ and gets completed in .................

(d) ............ is the largest gland in the human body. 

Solution 17:

1. The alimentary canal stretches from Mouth to Anus.
2. Teeth are rooted in separate Sockets in between the Gums.
3. Digestion of food starts in Buccal cavity and gets completed in Small Intestine.
4. The liver is the largest gland in the human body.

 

Question 18:  Following statements describe the five steps in animal nutrition. Read each statement and give one word for each statement. Write the terms that describe each process.

(a) Transportation of absorbed food to different parts of the body and their utilisation.

(b) Breaking of complex food substances into simpler and soluble substances.

(c) Removal of undigested and unabsorbed solid residues of food from the body.

(d) Taking food into the body.

(e) Transport of digested and soluble food from the intestine to blood vessels. 

Solution 18:

(a) Assimilation

(b) Digestion

(c) Egestion

(d) Ingestion

(e) Absorption

 

Short Answer Questions..................

 Question 19:  Match the animals in Column I with their mode of feeding listed in Column II

Solution 19:

 

Question 20:  Boojho took some grains of boiled rice in a test tube ‘A’ and Paheli took boiled and chewed rice in a test tube ‘B’. Both of them poured 1 – 2 drops of iodine solution into the test tube and observed the colour change. What colour change would they have observed? Give reasons for your answer. 

Solution 20:   The colour of boiled rice of test tube A changes to black-blue due to the reaction of iodine with starch by adding few drops of iodine solution but the colour of boiled and chewed rice of test tube will not change as salivary amylase has already acted on starch.

 

Question 21:  ‘A’ got her gall bladder removed surgically as she was diagnosed with stones in her gall bladder. After the surgery, she faced problems in the digestion of certain food items when consumed in bulk. Can you tell which kind of food items would they be and why? 

Solution 21:   The food items which contain fats will be hard to digest as presence of bile juice in the gall  bladder use to help the process of digestion of fat. A got her gall bladder removed in surgery which is creating trouble in the process of digestion of fat.

                                                             

Question 22:  Match the organs in Column I with the words listed in Column II.

Solution 22:

 

Question 23:  Ruminants such as cows and buffaloes swallow their food hurriedly and then sit restfully and chew their food. Can you reason why? 

Solution 23:   Ruminants usually eat their food hurriedly and then sit back and later on chew their food peacefully to digest their food which they kept as cuds.

                                                                                                                     

Question 24:  Boojho and Paheli were eating their food hurriedly so that they could go out and play during the recess. Suddenly, Boojho started coughing violently. Think of the reasons why he was coughing and discuss with your friends. 

Solution 24:   In the hurry of eating of food Boojho did not properly chewed the food and gulp the food with big bites. May be the food enters the windpipe rather than entering into oesophagus which causes coughing. Coughing clears the passage of windpipe. 

 

Long Answer Questions..................

 

Question 25:  Fill in the blanks using the words listed below.

(a) The digestion of all food components is completed by the ____________ juice.

(b) Large intestine absorbs __________ and some __________ from the undigested food.

(c) Tongue is attached at the _____________ to the floor of the mouth cavity and is free at the _____________.

(d) Amoeba pushes out _____________ around the food and traps it in a food _____________. 

Solution 25:

(a) The digestion of all food components is completed by the Intestinal juice.

(b) Large intestine absorbs water and some salts from the undigested food.

(c) Tongue is attached at the back to the floor of the mouth cavity and is free at the front.

(d) Amoeba pushes out Pseudopodia around the food and traps it in a food vacuole.

 

Question 26:  Label the below given Figure 2.1 as directed below in (i) to (iv) and give the name of each type of teeth.

 

(i) The cutting and biting teeth as ‘A’

(ii) The piercing and tearing teeth as ‘B’

(iii) The grinding and chewing teeth as ‘C’

(iv) The grinding teeth present only in adult as ‘D’ 

Solution 26:

(i) Incisors used in cutting and biting.

(ii) Canines used in piercing and tearing.

(iii) Premolars used in grinding and chewing.

(iv) Molars used in grinding and are present in adults.

 

 

Question 27:  Read the following passage carefully and answer the questions that follow it. Bile juice is stored in a sac called, gall bladder, located near its organ of secretion, liver. The gall bladder releases the bile juice into the small intestine whenever food reaches there. Though bile juice is devoid of any digestive enzymes, it is required for the digestion of fats. The fats cannot be digested easily because they are insoluble in water and are present as large globules. Bile juice breaks down big fat droplets into smaller droplets. These are then easily digested by the enzymes released from the pancreas.

(a) Which organ secretes the bile juice?

(b) Why is digestion of fats difficult as compared to that of other nutrients?

(c) How does bile juice help in digestion of fat?

(d) Where is the digestion of fat completed?

(e) Does bile juice digest fat completely? 

Solution 27:

(a) Liver secrets the bile juice.

(b) Digestion of fats is difficult as compared to other nutrients because fats are insoluble in water.

(c) Bile Juice breaks down big fat droplets into smaller droplets.

(d) Digestion of fat is complete in small intestine.

(e) No, bile juice did not digest fat completely.

 

Question 28:  Label the following parts in Figure 2.2 and name them.

(a) The largest gland in our body.

(b) The organ where protein digestion starts.

(c) The organ that releases digestive juice into the small intestine.

(d) The organ where bile juice gets stored. 

Solution 28:

(a) The largest gland in our body is liver.

(b) Stomach is the organ where protein digestion starts.

(c) Pancreas is the organ which releases digestive juice into the small intestine.

(d) Organ where bile juice get stored is Gall bladder.

 

 

Question 29:  Open your mouth, look into a mirror and try to count the different types of teeth in your mouth. Compare them with Figure 2.3 on page 13 of your NCERT textbook. Record your observations in the table below:

 

 

(a) Did you observe any difference in the number of teeth? If yes, could you identify which type of teeth showed the difference?

(b) Compare the number and type of teeth in an adult (say your parents or cousins who have reached the age of 25–30 or more). Note your observation.

Solution 29:

 

 

Question 30:  Solve the crossword given in Figure 2.3.

 

Across

1. Cream-coloured digestive gland

3. Undigested excretory solid residues

4. An organ that mixes saliva with the food

5. Point of defecation

7. Stored in the gall bladder

10. Finger-like outgrowth in the small intestine

13. Kind of taste buds

14. Kills bacteria in the stomach

Down

2. Feeds with the help of pseudopodia

6. Total number of molars in one jaw of an adult

8. Largest gland

9. Watery secretion in the mouth

11. A ruminant

12. Form of food chewed by ruminants 

Solution 30: