NCERT Exemplar Problems Class 7 Science – Transportation in Animals and Plants

Question 1:
The muscular tube through which stored urine is passed out of the body is called
(a) kidney ∴
(b) ureter
(c) urethra
(d) urinary bladder
Answer:
(c) The urine formed in kidneys goes into the urinary bladder through the tubes called ureters. The urine collected in bladder passed out from the body at regular intervals through the opening at the end of a tube called urethra.

Question 2:
They are pipe-like consisting of a group of specialised cells. They transport substances and form a two-way traffic in plants. Which of the following terms qualifies for the features mentioned above?
(a) Xylem tissue
(b) Vascular tissue
(c) Root hairs
(d) Phloem tissue
Answer:
(d) The vascular tissue called phloem forms a two-way traffic in plants for transport of substances. It carries the food from leaves to all other parts of plant.
The other options, i.e. xylem tissue carries water from the roots upwards to stem and leaves, vascular tissue consists of xylem and phloem vessels in plants and root hairs absorb water from the soil that moves from cell to cell in the root and ultimately enters the xylem vessels.

Question 3:
The absorption of nutrients and exchange of respiratory gases between blood and tissues takes place in
(a) veins
(b) arteries
(c) heart
(d) capillaries
Answer:
(d) Capillaries are the extremely thin blood vessels where exchange of substances and absorption of nutrients take place. Their thin walls facilitate the exchange.
They connect arteries (carry oxygenated blood from the heart) to veins (carry deoxygenated blood from all the parts of body to the heart).

Question 4:
In which of the following parts of human body are sweat glands absent?
(a) Scalp
(b) Armpits
(c) Lips
(d) Palms
Answer:
(c) Sweat glands are absent in lips.
These glands produce a liquid waste called sweat that contains water, salts and little urea. These are found over most of the body part.

Question 5:
In a tall tree which force is responsible for pulling water and minerals from the soil?
(a) Gravitational force
(b) Transportation force
(c) Suction force
(d) Conduction force
Answer:
(c) In a tall tree, suction force is generated by continuous evaporation of water (transpiration), that pulls up water and minerals absorbed by the roots from the soil to reach the leaves.

Question 6:
Aquatic animals like fish excrete their wastes in gaseous form as
(a) oxygen
(b) hydrogen
(c) ammonia
(d) nitrogen
Answer:
(c) The way in which waste product are excreted from the body of an animal depends on the availability of water to it. Aquatic animals live in water, so they excrete cell waste in gaseous form as ammonia which directly dissolves in water.

Very Short Answer Type Questions

Question 7:
Veins have valves which allow blood to flow only in one direction. Arteries do not have valves. Yet the blood flows in one direction only. Can you explain why?
Answer:
Veins have valves to prevent blood from flowing backwards. Arteries also carry blood only in one direction but they do not have valves.
This is because the blood flows through them at high pressure. Their thick and elastic walls can withstand the high pressure of blood.

Question 8:
What is the special feature present in a human heart which does not allow mixing of blood when oxygen rich and carbon dioxide rich blood reach the heart?
Answer:
In human, the heart has four chambers. The two upper chambers are called the atria and the two lower chambers are called the ventricles.
On the left side are the left atrium and left ventricle and on the right side of the heart are right atrium and right ventricle.
The left side of the heart is completely separated from its right side by means for a partition of thick muscles called the septum. This septum prevents the mixing of oxygenated blood on the left side with the deoxygenated blood on its right side.

Question 9:
Name the organ which is located in the chest cavity with its lower tip slightly tilted towards the left.
Answer:
The heart is the organ located in the chest cavity with its lower tip slightly tilted towards the left. It is roughly the size of a fist and beats continuosly to act as pump for the transport of blood.

Short Answer Type Questions

Question 10:
Look at figure and draw another figure of the same set-up as would be observed after a few hours.

Answer:
After a few hours, the same set-up would be as shown as below:

This figure shows that there will be an increase in the level of sugar solution in the potato piece. The level of sugar solution can rise only if some water from the petridish passes through the wall of potato and goes inside it.
Since, the water level has risen, it shows that water can move from cell to cell in the potato wall and reaches inside the cavity.

Question 11:
Arrange the following statements in the correct order in which they occur during the formation and removal of urine in human beings.
(a) Ureters carry urine to the urinary bladder.
(b)Wastes dissolved in water are filtered out as urine in the kidneys.
(c)Urine stored in urinary bladder is passed out through the urinary opening at the end of the urethra.
(d)Blood containing useful and harmful substances reaches the kidneys for filtration.
(e) Useful substances are absorbed back into the blood.
Answer:
The correct order of the formation and removal of urine in human beings is
(d) Blood containing useful and harmful substances reaches the kidneys for filtration.
(e) Useful substances are absorbed back into the blood.\
(b) Wastes dissolved in water is filtered out as urine in the kidneys.
(a) Ureters carry urine to the urinary bladder.
(c)Urine stored in urinary bladder is passed out through the urinary opening at the end of the urethra.

Question 12:
Paheli uprooted a rose plant from the soil. Most of the root tips, with root hairs got left behind in the soil. She planted it in a pot with new soil and watered it regularly. Will the plant grow or die? Give reason for your answer.
Answer:
Possible answers are:
(i) Without the root hairs, the roots will not be able to absorb water and nutrients and the plant will die.
(ii) The stem of the rose plant may grow new roots and the plant will live.
(iii) The rose plant may not be able to survive in a different type of soil.

Question 13:
(a) Name the only artery that carries carbon dioxide rich blood.
(b) Why is it called an artery if it does not carry oxygen-rich blood?
Answer:
(a) The only artery that carries carbon dioxide rich blood is pulmonary artery. It carries deoxygenated blood from the right ventricle of the heart to the lungs.
(a) The main function of artery is to carry blood away from the heart. Also, arteries have thick walls and do not contain valves. Blood flow in arteries, takes place at high pressure. All these characteristics are found in pulmonary artery. It carries away deoxygenated blood from heart to lungs for oxygenation, therefore it is called an artery.

Question 14:
Boojho’s uncle was hospitalised and put on dialysis after a severe infection in both of his kidneys.
(a) What is dialysis?
(b) When does it become necessary to take such a treatment?
Answer:
(a) Dialysis is the process of filtering blood periodically for removing wastes through an artificial kidney.
(b) It becomes necessary to take such a treatment when there is complete failure of both the kidneys. In such cases, accumulation of urea in the person’s blood takes place. This can ultimately kill the person if the blood is not filtered artificially.

Question 15:
Name the process and the organ which helps in removing the following wastes from the body.
(a) Carbon dioxide
(b) Undigested food
(c) Urine
(d) Sweat
Answer:
The process, waste and the organ involved in removal are as given below:

Question 16:
Observe the figure and answer the given questions:
(a) Name the instrument.
(b) Label the parts A, B and C.

Answer:
(a) The name of the given instrument is stethoscope. It is a device used to amplify the sound of the heart. It consists of a chest piece that carries a sensitive diaphragm, two ear pieces and a tube joining the parts
(b) Labelled diagram of stethoscope

Question 17:
Paheli noticed water being pulled up by a motor pump to an overhead tank of a five storeyed building. She wondered how water
moves up to great heights in the tall trees standing next to the building. Can you tell how?
Answer:
When the water is pulled up by a motor-pump to an overhead tank of a five storeyed building, it moves to a great height due to the suction pull created by the pump. This pull forms a continuous column of water and water rises up to a great height.
Similarly, when transpiration occurs in the leaves of a tall tree, water is evaporated through the pores called stomata. The continuous evaporation creates a suction force.
Due to this suction force, water from the soil rises up through the roots of the plants and reaches to a great height in tall trees.

Long Answer Type Questions

Question 18:
Match the parts of the heart in column I with the direction of flow of blood in column II.

Answer:
The correct matching is as given:
(a)—(i),
(b)-(iv),
(c)—(vi).
(d)-(ii).
(e)—(v).
(f)-(iii)

Question 19:
Read the following terms given below.

Group the terms on the basis of the categories given below.
(a) Circulatory system of animals.
(b) Excretory system in human.
(c) Transport of substances in plants
Answer:
The terms on the basis of the categories mentioned above can be grouped as follows:
(a) Circulatory system of human Arteries, atria, capillaries, veins, heart.
In the circulatory system, the heart (consists of two atria and two ventricles) acts as a pump to put out blood. The blood vessels (arteries, veins and capillaries) act as tubes through which blood flows in the whole body.

(b) Excretory system in human Urethra, kidneys, ureter and urinary bladder.
The excretory system of human consists of two bean-shaped kidneys that filter blood to form urine. Urine goes into the urinary bladder through tubes called ureters. It goes out from body through the opening at the end of a tube called urethra.

(c) Transport of substances in plants Root hairs, xylem and phloem.
Transport system in plants consists of xylem and phloem. The water absorbed by root hairs from soil reaches xylem to move upward to stem, branches and leaves. Phloem carries food from leaves to other parts.

Question 20:
Fill in the blanks of the following paragraph using just two words, arteries and veins.
…… (a)…….. carry oxygen rich blood from the heart to all parts of the body and……. (b)…….. carry carbon dioxide rich blood from all parts of the body back to the heart………………… (c)……… have thin walls and …… (d)…….. have thick elastic walls. Blood flows at high pressure in …… (e)……….. Valves are present in ………. (f)….. which allow blood to flow only towards the heart………….(g)…… divide into smaller vessels.
These vessels further divide into extremely thin tubes called capillaries.
The capillaries join up to form………..(h)……….. .
Answer:
(a) Arteries
(b) veins
(c) Veins
(d) arteries
(e) arteries
(f) veins
(g) Arteries
(h) veins

Question 21:
While learning to ride a bicycle, Boojho lost his balance and fell. He got bruises on his knees and it started bleeding. However, the bleeding stopped after sometime.
(a) Why did the bleeding stop?
(b) What would be the colour of the wounded area and why?
(c) Which type of blood cells are responsible for clotting of blood?
Answer:
(a) A wound stops bleeding after sometime due to the process of clot formation. It plugs the cut and bleeding stops.
(b) Wounded area becomes dark red in colour due to the clotting of blood.
(c) The blood clot is formed due to the presence of the cells called platelets in the blood.