NCERT Exemplar solutions for Science [English] Class 7 chapter 2 - Nutrition in Animals [Latest edition]

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 a blue-black colour when tested with iodine?

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

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?

The swallowed food moves downwards in the alimentary canal because of

The acid present in the stomach

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

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

1. They have very thin walls.
2. They have a network of thin and small blood vessels close to the surface.
3. They have small pores through which food can easily pass.
4. They are finger-like projections

Identify those statements which enable the villi to absorb digested food.

The false feet of Amoeba is used for

The enzymes present in the saliva convert

Cud is the name given to the food of ruminants which is

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

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

Name the parts of the alimentary canal where

water gets absorbed from undigested food

Name the parts of the alimentary canal where

digested food gets absorbed

Name the parts of the alimentary canal where

taste of the food is perceived

Name the parts of the alimentary canal where

bile juice is produced

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

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

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

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

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

Mucus protects the stomach lining from damage.

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

All heterotrophs have a similar basic process of nutrition.

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

liver, salivary gland, starch, gall bladder

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

stomach, liver, pancreas, salivary gland

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

tongue, absorption, taste, swallow

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

oesophagus, small intestine, large intestine, rectum

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?

The alimentary canal stretches from ______ to ______.

Teeth are rooted in separate ______ in between the ______.

Digestion of food starts in ______ and gets completed in ______.

______ is the largest gland in the human body.

The 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.

Transportation of absorbed food to different parts of the body and their utilisation

The 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.

Breaking of complex food substances into simpler and soluble substances.

The 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.

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

The 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.

Taking food into the body.

The 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.

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

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

Boojho took some grains of boiled rice in test tube ‘A’ and Paheli took boiled and chewed rice in 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.

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?

Match the organs in Column I with the words listed in Column II.

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

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

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

Large intestine absorbs ___________ and some __________ from the undigested food.

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

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

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

1. The cutting and biting teeth as ‘A’
2. The piercing and tearing teeth as ‘B’
3. The grinding and chewing teeth as ‘C’
4. The grinding teeth are present only in adults as ‘D’

Read the following passage carefully and answer the questions that follow it. Bile juice is stored in a sac called, the gall bladder, located near its organ of secretion, the 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.

1. Which organ secretes the bile juice?
2. Why is digestion of fats difficult as compared to that of other nutrients?
3. How does bile juice help in the digestion of fat?
4. Where is the digestion of fat completed?
5. Does bile juice digest fat completely?

Label the following parts in Figure 2.2 and name them.

1. The largest gland in our body.
2. The organ where protein digestion starts.
3. The organ that releases digestive juice into the small intestine.
4. The organ where bile juice gets stored.

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:

1. Did you observe any difference in the number of teeth? If yes, could you identify which type of teeth showed the difference?
2. 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.

Solve the crossword given in Figure 2.3.