Answers to NCERT Solutions for Class 7
Science Chapter 11 Transportation in Animals and Plants
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1. Match structures given in Column I with
functions given in Column II.
|
Column- I |
Column-II |
|
(i) Stomata |
(a) Absorption of water |
|
(ii) Xylem |
(b) Transpiration |
|
(iii) Root hairs |
(c) Transport of food |
|
(iv) Phloem |
(d) Transport of water |
|
(e) Synthesis of carbohydrates |
Solution:
|
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 _____________.
(ii) Haemoglobin is
present in _____________ cells.
(iii) Arteries and
veins are joined by a network of _____________.
(iv) The rhythmic
expansion and contraction of the heart is called the _____________.
(v) The main excretory
product in human beings is _____________.
(vi) Sweat contains
water and _____________.
(vii) Kidneys eliminate
the waste materials in the liquid form called _____________.
(viii) Water reaches
great heights in the trees because of suction pull caused by _____________.
Solution:
(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 the heartbeat.
(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
(iv) covered with a
polythene bag
Solution:
a) i) xylem
b) iii) under the fan
4. Why is the
transport of materials necessary in a plant or in an animal? Explain.
Solution:
Transport of materials
is necessary for both plants and animals as every cell needs a regular supply
of nutrients and oxygen to release energy through respiration.
The food that we eat
is broken down into smaller components to be absorbed by cells. The oxygen we
inhale also has to be transported to all the cells of the body. Our body also
requires the constant removal of waste materials such as carbon dioxide.
For the transport of
all these materials (nutrients, oxygen and waste products), our body has a
specialised transport system.
Similarly, in plants,
the transport of water and food is accomplished with the help of vascular
tissues (xylem and the phloem).
5. What will happen if
there are no platelets in the blood?
Solution:
If there are no
platelets, then blood will not clot as platelets release blood clotting factor
at the site of injury and stop further bleeding.
6. What are stomata?
Give two functions of stomata.
Solution:
Tiny pores present on
the leaf surface are known as stomata.
Functions of stomata
- It helps in the exchange of
gases
- Evaporation of water through
leaves occurs due to stomata.
7. Does transpiration
serve any useful function in plants? Explain.
Solution:
Transpiration serves
the following functions in plants
- It helps in lowering the
temperature of plants, thus preventing heat injury to plants.
- It helps in transpiration pull,
which helps in raining water on higher plants.
- It also causes loss of water
absorbed by plants.
8. What are the
components of blood?
Solution:
The components of
blood are red blood cells, white blood cells, platelets and plasma.
9. Why is blood needed
by all the parts of a body?
Solution:
Blood is a significant
part of the transport system in our body, and we need blood for the following
reasons:
- For the transport of oxygen to
all parts of our body
- To expel carbon dioxide from
our body
- To transmit heat, thus helping
in the regulation of body temperature.
- It is required to fight out
infections and diseases.
10. What makes the
blood look red?
Solution:
The presence of a red
pigment called haemoglobin in red blood cells (RBC) makes the blood
appear red.
11. Describe the
function of the heart.
Solution:
The heart is an organ
which beats continuously to act as a pump for the transport of blood, which
carries other substances with it. The heart has four chambers. The two upper
chambers are called the atria (singular: atrium), and the two lower chambers
are called the ventricles. The partition between the chambers helps to avoid
mixing up blood-rich in oxygen with the blood-rich in carbon dioxide. Blood
flows from the heart to the lungs and back to the heart, from where it is
pumped to the rest of the body.
12. Why is it necessary to excrete waste products?
Solution:
When the cells in the body perform their functions, certain waste products are released. These are toxic and hence need to be removed from the body.
13. Draw a diagram of the human excretory system and label the various parts.
Solution:
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