Why are valves present in veins?
Answer and explanation
Correct answer: To prevent backflow of blood
Veins return blood from body tissues to the heart, and the pressure inside them is comparatively low. In many veins, especially those of the limbs, blood must move against gravity. Valves open when blood flows toward the heart and close if it starts to reverse, thereby preventing backflow and supporting one-way circulation. Therefore option A is correct; valves do not colour blood, manufacture oxygen, or digest food.
Frequently asked questions
What is the correct answer to this question?
To prevent backflow of blood
Why is this the correct answer?
Veins return blood from body tissues to the heart, and the pressure inside them is comparatively low. In many veins, especially those of the limbs, blood must move against gravity. Valves open when blood flows toward the heart and close if it starts to reverse, thereby preventing backflow and supporting one-way circulation. Therefore option A is correct; valves do not colour blood, manufacture oxygen, or digest food.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: World of Living. Topic: Life Processes.
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