What prevents the backflow of blood inside the heart during contraction?(a) thick muscular walls of ventricles (b) valves(c) thin walls of atria (d) all of the above

Academic Biology NCERT Class 10

(b) valves

Valves prevent the backflow of blood inside the heart during contraction, because it allows the blood flow in only one direction.

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Updated on: 24-Mar-2023

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Blood is pumped from the heart to the entire body by the:(a) lungs (b) ventricles (c) atria (d) nerves
Give Reasons: (a) Ventricles Have Thicker Muscular Walls Than Atria. (b) Transport System in Plants Is Slow. (c) Circulation of Blood in Aquatic Vertebrates Differs from That in Terrestrial Vertebrates. (d) During The Daytime, Water and Minerals Travel Faster Through the Xylem as Compared to The Night. (e) Veins Have Valves Whereas Arteries Do Not.
(a) Mention any two components of blood.(b) Trace the movement of oxygenated blood in the body.(c) Write the function of valves present in between atria and ventricles.(d) Write one structural difference between the composition of artery and veins.
Ventricles are thick walled in the heart of mammals. Give Reasons.
The walls of large intestine absorb(a) Water(b) Proteins (c) Cellulose(d) Roughage
The clotting of blood is to(a) Slow down the movement of blood inside the blood vessel.(b) trap oxygen inside the blood so that it may be transported more easily.(c) seal up wounds to avoid loss of blood(d) all the above are correct
Which one of the following does not have valves?(a) heart (b) arteries (c) capillaries (d) veins
(a) What are the upper parts of the heart called ?(b) What are the lower parts of the heart called ?(c) What is the name of blood vessels which connect arteries to veins ?(d) (i) Which side of the heart pumps blood into the lungs?(ii) Which side of the heart pumps blood into entire body (except the lungs)?
(a) How many types of blood vessels are there in the human body ? Name them.(b) Why does the heart need valves ?
Veins and arteries carry blood. Which of these carry blood :(a) away from the heart ?(b) back to the heart ?
In an electric bulb, light is produced due to the glowing of$(a)$. the glass case of the bulb$(b)$. the thin filament$(c)$. the thick wires supporting the filament$(d)$. gases inside glass case of the bulb.
DIRECTIONS: Read the passage (s) given below and answer the questions that follow. Passage - 1 Heart is an organ which beats continuously to act as a pump for transport of blood, which carries other substances. The heart is located in the chest cavity with its lower tip slightly tilted towards the left. Your heart is roughly the size of your fist. To avoid the mixing of blood rich in oxygen and the blood in carbon dioxide, the heart has (a) two atria(b) two ventricles(c) four chambers(d) none of these
What is the importance of blood, heart and veins?
The hump of the camel is a reservoir of(a) fatty tissue(b) water(c) milk(d) all of above
Filament of a torch bulb is$(a)$. a metal case$(b)$. metal tip at the centre of the base$(c)$. two thick wires$(d)$. a thin wire.

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