Life Processes
What could be the possible explanation for the evolution of four-chambered heart in mammals as opposed to two-chambered heart in fishes?
Fishes do not require energy to maintain their body temperature.
Fishes have efficient gills.
Mammals have more complex structure than fishes.
Both A and C
Both A and C
In fishes and reptiles, the heart is two-chambered and there is mixing of oxygenated and deoxygenated blood. They are cold blooded (the body temperature varies according to the surrounding temperature), so energy is required only for locomotion and hence less amount of oxygen is sufficient in them. Birds and mammals are warm blooded, so more energy is required to keep up the body temperature. To maintain high energy requirements of the body, more oxygen supply is required. Therefore, the heart has four chambers and oxygenated blood and deoxygenated blood is kept strictly separated. Also, complexities in the body structure and different mechanisms have increased with evolution. Therefore the mechanism of circulation has also evolved.
Both A and C In fishes and reptiles, the heart is two-chambered and there is mixing of oxygenated and deoxygenated blood. They are cold blooded (the body temperature varies according to the surrounding temperature), so energy is required only for locomotion and hence less amount of oxygen is sufficient in them. Birds and mammals are warm blooded, so more energy is required to keep up the body temperature. To maintain high energy requirements of the body, more oxygen supply is required. Therefore, the heart has four chambers and oxygenated blood and deoxygenated blood is kept strictly separated. Also, complexities in the body structure and different mechanisms have increased with evolution. Therefore the mechanism of circulation has also evolved.
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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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