Life Processes
Which of the following help veins to prevent the backflow of blood?
Thick walls
Valves
Elastic walls
Heart beat
Valves
Veins collect blood from different parts of the body and bring it back to the heart. They do not need thick walls because the blood is no longer under pressure, but instead, they have valves to ensure that the blood flows only in one direction towards the heart.
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The process of obtaining food to meet the energy demands of the body is known as:A. excretion
B. respiration
C. nutrition
D. circulation
The process involving oxidation of food to release energy is known as _________ .
A. breathing
B. excretion
C. circulation
D. respiration
What is the function of the sac-like structures present at the end of bronchioles?
A. Storage of respiratory gases
B. Exchange of respiratory gases
C. Protection of lungs
D. Protection from bacteria
Exchange of gases in alveoli occurs through:
A. absorption
B. dialysis
C. diffusion
D. anaerobic respiration
The process of digestion of food starts in the:
A. mouth
B. stomach
C. small intestine
D. oesophagus
The smallest blood vessel of the circulatory system is known as the:
A. artery
B. vein
C. capillary
D. aorta
Where does digestion of proteins take place?
A. Stomach only
B. Stomach and small intestines
C. Stomach and large intestines
D. Large intestines only
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