Page 97 - Ripples SCIENCE 7 - TEJPUR Edition 2024 Answer Key

6. What is the other name for red blood cells and white blood cells?

Ans. Erythrocytes & Leucocytes
7. What is the name of the artificial process by which blood is purified when kidneys

fail?
Ans. Dialysis

E. Short-answer questions

1. Define urine.
Ans. Urine-It is a liquid waste made by the kidneys that contains water, salts and waste

products. It is stored in the urinary bladder until 1 it is released from the body through
urination, helping remove excess water & toxins to maintain body balance.

2. Name the various parts of circulatory system.
Ans. The circulatory system consists of following parts.

(a) Heart : A muscular organ that pumps blood throughout the body.

(b) Blood Vessels :
(i) Arteries : Carry oxygen-rich blood away from the heart to the body.

(ii) Veins : Return oxygen-depleted blood back to the heart.
(iii) Capillaries : Tiny vessels where gas exchange & nutrient exchange occur

between blood & tissues.
(c) Blood: A fluid that carries nutrients, oxygen, carbon dioxide and waste products

throughout the body. It consists of RBCs, WBCs, platelets & plasma.

3. What function is performed by liver in the process of excretion?
Ans. The liver helps remove harmful substances from the body by breaking them down. It

also produces bile, which aids in digestion & carries waste out through the intestines.
4. Name and write one main function of various types of blood cells.

Ans. The various types of blood cells are :
(a) Red Blood Cells (RBCs) : They carry oxygen from the lungs to all tissues of the

body & transport carbon dioxide back to the lungs for exhalation.

(b) White Blood Cells (WBCs) : These defend the body against infections and germs.
(c) Platelets : They play a crucial role in blood clotting.

5. Blood is a fluid connective tissue. Explain.
Ans. Blood is classified as a fluid connective tissue because it contains cells suspended in a

fluid called plasma. Plasma is mainly composed of water, proteins & other substances.
The cells in blood include RBCs, which carry oxygen throughout the body; WBCs,

which defend against infections and platelets, which help in blood clotting. Together
these components help blood to accomplish its functions.

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