Class 7 Science

Transportation in Organisms

NCERT Solution

Question 1: Match structures given in Column I with functions given in Column II.

Column IColumn II
(1) Stomata(a) Absorption of water
(2) Xylem(b) Transpiration
(3) Root hairs(c) Transport of food
(4) Phloem(d) Transport of water

Answer: 1 → b, 2 → d, 3 → a, 4 → c

Question 2: Fill in the blanks.

  • The blood from the heart is transported to all parts of the body by the ………….
  • Haemoglobin is present in ………….cells.
  • Arteries and veins are joined by a network of …………
  • The rhythmic expansion and contraction of the heart is called…………..
  • The main excretory product in human beings is ………………
  • Sweat contains water and …………….
  • Kidneys eliminate the waste materials in the liquid form called …………..
  • Water reaches great heights in the trees because of suction pull caused by ………..

Answer: (i) Heart, (ii) Red blood, (iii) Capillaries, (iv) heart beat, (v) urea, (vi) waste products, (vii) urine, (viii) transpiration


Question 3: Choose the correct options:

(a) In plants, water is transported through

  • Xylem
  • Phloem
  • Stomata
  • Root hair

Answer: (i) Xylem

(b) Water absorption through roots can be increased by keeping the plants

  • in the shade
  • in dim light
  • under the fan
  • covered with a polythene bag

Answer: (iii) Under the fan

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

Answer The cells of plants and animals need various substances to carry out important metabolic activities. Further, many waste products are created during these metabolic activities. Transport of materials is necessary to supply various substances and to remove waste products.

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

Answer: Platelets are responsible for clotting of blood. If there are no platelets, the blood would not clot in case of an injury. This will lead to excess blood loss and finally in death of the person.



Question 6: What are stomata? Give two functions of stomata.

Answer: The numerous pores on the surface of leaf are called stomata. Transpiration and exchange of gases (carbon dioxide and oxygen) are some of the functions of stomata.

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

Answer: Transpiration serves important functions in plants. Transpiration creates the transpiration pull; which is responsible for the rise of water to great heights in tall plants and other trees.

Question 8: What are the components of blood?

Answer: The main components of blood are: Plasma, Blood Cells and Platelets.

Question 9: Why is blood needed by all the parts of a body?

Answer: Blood acts as a carrier of various substances. Every part of the body needs certain substances to perform its functions. Additionally, every part creates some waste products. Blood is needed by all parts of the body so that various substances can be supplied to them and waste can be removed from them.



Question 10: What makes the blood look red?

Answer: Blood is red because of the presence of a pigment; called haemoglobin.

Question 11: Describe the function of the heart.

Answer: The heart is a pumping organ which pumps the blood. The heart pumps the deoxygenated blood to the lungs; for oxygenation. Moreover, the heart pumps the oxygenated blood to different parts of the body.

Question 12: Why is it necessary to excrete waste products?

Answer: Waste products can prove lethal if not removed in time. Hence, it is necessary to excrete the waste products.

Question 13: Draw a diagram of the human excretory system and label the various parts

Answer:

human excretory system