Why is blood needed by all the parts of a body?
Blood is needed by all the parts of our body because it performs the following important functions in our body and also known as the ‘river of life’:
1. Blood helps in the transportation of food by the plasma from the alimentary canal and liver to all the parts of the body for growth, repair and energy.
2. Blood carries water to all the parts of the body and water balance regulation occurs which is important in the metabolic processes.
3. Blood component; RBCs carries oxygen bound to haemoglobin as the oxyhaemoglobin from the lungs to the tissues for oxidation of food to release energy.
4. Blood component plasma; collects the carbon dioxide from the body tissues and carries it to the lungs for breathing out from the body.
5. Blood component plasma; carries a waste product such as urea, uric acid and creatinine from the liver and other tissues to the kidneys for excretion in urine.
6. Blood protects the body from diseases because it contains white blood cells that kills bacteria and other germs. They act as the soldiers, scavengers and builders of the body.
7. Blood helps in the regulation of body temperature.
Popular Questions of Class 7 Science
- Q:-
Classify the changes involved in the following processes as physical or chemical changes:
(a) Photosynthesis
(b) Dissolving sugar in water
(c) Burning of coal
(d) Melting of wax
(e) Beating aluminium to make aluminium foil
(f ) Digestion of food - Q:-
Given below is a crossword puzzle based on this lesson. Use hints to fill in the blank spaces with letters that complete the words.
Down Across
(D) 1 : Thorough washing (A) 1 : Keeps warm
2 : Animal fibre 2 : Its leaves are eaten by silkworms
3 : Long thread like structure 3 : Hatches from egg of moth
- Q:-
Sketch the cross section of soil and label the various layers.
- Q:-
Take three test-tubes. Fill æth of each with water. Label them A, B and C. Keep a snail in test-tube A, a water plant in test-tube B and in C, keep snail and plant both. Which test-tube would have the highest concentration of CO2?
- Q:-
When baking soda is mixed with lemon juice, bubbles are formed with the evolution of a gas. What type of change is it? Explain.
- Q:-
Here is a crossword puzzle: Good luck!
Across
3. Liquid waste products
4. Solid waste extracted in sewage treatment
6. A word related to hygiene
8. Waste matter discharged from human bodyDown
1. Used water
2. A pipe carrying sewage
5. Micro-organisms which causes cholera
7. A chemical to disinfect water - Q:-
Match the items in Column I with those in Column II:
Column I Column II
(i) A home for living organisms (a) Large particles
(ii) Upper layer of the soil (b) All kinds of soil
(iii) Sandy soil (c) Dark in colour
(iv) Middle layer of the soil (d) Small particles and packed tight (v) Clayey soil (e) Lesser amount of humus - Q:-
Write one similarity and one difference between the nutrition in amoeba and human beings.
- Q:-
An iron ball at 40°C is dropped in a mug containing water at 40°C. The heat will
(a) flow from iron ball to water.
(b) not flow from iron ball to water or from water to iron ball.
(c) flow from water to iron ball.
(d) increase the temperature of both. - Q:-
Why does an athlete breathe faster and deeper than usual after finishing the race?
Recently Viewed Questions of Class 7 Science
- Q:-
What is a virtual image? Give one situation where a virtual image is formed.
- Q:-
Fill in the blanks with the appropriate answers:
(a) People obtain groundwater through________ and ________. (b) Three forms of water are ________, ________ and ________.
(c) The water bearing layer of the earth is ________.
(d) The process of water seepage into the ground is called ________. - Q:-
Mark ëTí if the statement is true and ëFí if it is false:
(i) During heavy exercise the breathing rate of a person slows down. (T/F)
(ii) Plants carry out photosynthesis only during the day and respiration only at night. (T/F)
(iii) Frogs breathe through their skins as well as their lungs. (T/F)
(iv) The fishes have lungs for respiration. (T/F)
(v) The size of the chest cavity increases during inhalation. (T/F) - Q:-
How do elephant living in the tropical rainforest adapt itself?
- Q:-
Which option best describes a tropical region?
(i) hot and humid
(ii) moderate temperature, heavy rainfall
(iii) cold and humid
(iv) hot and dry - Q:-
Discuss why wearing more layers of clothing during winter keeps us warmer than wearing just one thick piece of clothing.
- Q:-
Explain how painting of an iron gate prevents it from rusting.
- Q:-
There are ten tubewells in a lane of fifty houses. What could be the long term impact on the water table?
- Q:-
Tick the correct answer:
(a) In cockroaches, air enters the body through
(i) lungs (ii) gills
(iii) spiracles (iv) skin(b) During heavy exercise, we get cramps in the legs due to the accumulation of
(i) carbon dioxide (ii) lactic acid
(iii) alcohol (iv) water(c) Normal range of breathing rate per minute in an average adult person at rest is:
(i) 9ñ12 (ii) 15ñ18
(iii) 21ñ24 (iv) 30ñ33(d) During exhalation, the ribs
(i) move outwards (ii) move downwards
(iii) move upwards (iv) do not move at all - Q:-
State two differences between a convex and a concave lens.
- NCERT Chapter