Wednesday, 20 April 2016

TEXTBOOK ANSWERS AND SOLUTIONS OF CBSE CLASS VII SCIENCE Chapter 11 Transportation in Animals and Plants

1) Match structures given in Column I with functions given in Column II.

Column I                                Column II
(i) Stomata.                             (b) Transpiration
(ii) Xylem                                (d) Transport of water
(iii) Root hairs                         a) Absorption of water
(iv) Phloem                              c) Transport of food

2) Fill in the blanks.

(i) The blood from the heart is transported to all parts of the body by the _arteries__.
(ii) Haemoglobin is present in __red blood__ cells.
(iii) Arteries and veins are joined by a network of _capillaries__ .
(iv) The rhythmic expansion and contraction of the heart is called __heart beat__.
(v) The main excretory product in human beings is __urea__ .
(vi) Sweat contains water and __salts __.
(vii) Kidneys eliminate the waste materials in the liquid form called __urine __.
(viii) Water reaches great heights in the trees because of suction pull caused by __transpiration_ _.

3) Choose the correct option:
(a) In plants, water is transported through
(i) xylem
(ii) phloem
(iii) stomata
(iv) root hair
(b) Water absorption through roots can be increased by keeping the plants
(i) in the shade
(ii) in dim light
iii. under the fan
iii. covered with a polythene bag

(a) (i) xylem
(b) (iii) under the fan

4) Why is transport of materials necessary in a plant or in an animal? Explain.

ANSWER:-Transport of materials is necessary for plants or animals because due to it the nutrients and oxygen are made available to all the parts of the body. If the transport of necessary nutrients and oxygen does not take place in the body, the body will not be able to survive.

5) What will happen if there are no platelets in the blood?

ANSWER:-If there are no platelets in the blood, then the blood would not be able to clot.

6) What are stomata? Give two functions of stomata

ANSWER:-There are small openings on the lower surface of the leaves. These pores are called stomata. These openings are surrounded with guard cells.

Functions of stomata:
1. It helps in the transpiration of water, i.e., the loss of excess water from the plant.
2. Loss of water from the stomata creates an upward pull, i.e., suction pull which helps in absorption of water from the roots.
3. They help in exchange of gases.

7) Does transpiration serve any useful function in the plants? Explain.

i) It helps to enhance the absorption of water and dissolved minerals by creation of a suction pull.
(ii) It helps in getting rid of the excess water.
(iii) It helps in transport of water and minerals to leaves and leaves use the water for photosynthesis.
(iv)It produces a cooling effect on the plant

8) What are the components of blood?

ANSWER: - There are four components of blood:

(i) Plasma is liquid parts of bloods which is yellowish in colour and contain 90% water. It contains food, enzymes, wastes and proteins etc

(ii) Red blood cells are disc shaped cells containing red coloured pigment called haemoglobin in it. Haemoglobin helps in transportation of oxygen.

(iii) White blood cells are the fighting cells which protect us against bacteria and foreign materials causing infections.

(iv) Platelets help in clotting of the blood.

8) Why is blood needed by all the parts of a body?

ANSWER:-Blood is needed by all the parts because it contains the digested food and oxygen in it.
It supplies the oxygen and digested food to various parts of the body to provide essential energy to them which helps the body to perform various functions

10) What makes the blood look red?

ANSWER:-The presence of haemoglobin, a red pigment in the red blood cells (RBCs) makes blood appear red in colour. The haemoglobin carries oxygen and transports it to all the parts of the body.

11) Describe the function of the heart.

ANSWER: - The right auricle and ventricle receive blood with carbon dioxide from all parts of the body. The collected blood is then pumped to the lungs for the purification. In lungs, the exchange of gases takes place and purified blood is sent back to left auricle. It pumps it to the left ventricle, which in turn pumps off the purified blood to all parts of body through arteries.

12) Why is it necessary to excrete waste products?

ANSWER:-All cells of our body produce waste products. These waste products are toxic to the body and therefore need to be excreted out. This process of removing waste products produced in the cells of living organisms is called excretion.

13) Draw a diagram of the human excretory system and label the various parts.