Question

17)

Read the following and answer questions from 17 (i) to 17 (v).

Heart is a muscular organ that pumps blood to different parts of the body. It has upper and
lower chambers which are called atria and ventricles respectively. The valves present in the heart
ensure unidirectional flow of blood.
17.(1) Which of the following parts of the heart has thickest wall ?
a) Right ventricle b) Left atrium
c) Left ventricle
d) Right atrium.
17.(ii) What prevents backflow of blood inside the heart during contraction ?
a) Valves in heart
b) Thick muscular walls of ventricles.
c) Thin muscular wall of atria
d) All of the above.
17.(iii) In humans the blood leaving the left part of heart is rich in
a)Water (b) Oxygen (c) Haemoglobin d) Carbon dioxide
17.(iv) Choose the incorrect statement from the following that relates to arteries
a)
They have thick elastic walls as compared to veins.
b) They bring blood from tissues toward the heart
c)They generally lack valves.
d) Their lumen is wide
17(v) Only....
have completely divided four chambered heat.
a) Reptiles and birds
c) Fishes and amphibians
b) Fishes and reptiles. d) Birds and mammals
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Answer 1

17(i)left ventricle

(ii)valves in heart

(iii) oxygen

(iv)b

(v)A

Answer 2

Answer:

i) A. Right Ventricle

ii) A. Valves in heart

iii) B. Oxygen

iv) B. They bring blood from tissues toward the heart.

v) D. Birds and Reptiles