Science
Assertion (A) : The rate of breathing in aquatic organisms is much faster than in terrestrial organisms.
Reason (R) : The amount of oxygen dissolved in water is very high as compared to the amount of oxygen in air.
options
- (A) and (R) are true and (R) is the reason for (A).
- (A) and (R) are true and (R) is not the reason for (A).
- (A) is true, but (R) is false.
- (A) is false, but (R) is true.
Answer
(A) is true, but (R) is false.
Reason —
Assertion (A) is true because aquatic organisms like fish have to take in water continuously through their gills to obtain the oxygen dissolved in it. Since the amount of oxygen available in water is very limited, they must breathe faster to meet their energy needs.
Reason (R) is false because the amount of oxygen dissolved in water is much lower than the amount of oxygen present in air. That’s why aquatic organisms need to breathe faster — to extract enough oxygen from the limited supply in water.
Hence, (A) is true, but (R) is false.
Related Questions
Assertion (A) : Hydrogen gas is not evolved when zinc reacts with nitric acid.
Reason (R) : Nitric acid oxidises the hydrogen gas produced to water and itself gets reduced.
options
- (A) and (R) are true and (R) is the reason for (A).
- (A) and (R) are true and (R) is not the reason for (A).
- (A) is true, but (R) is false.
- (A) is false, but (R) is true.
Assertion (A) : Accumulation of harmful chemicals is maximum in the organisms at the highest trophic level of a food chain.
Reason (R) : Harmful chemicals are sprayed on the crops to protect them from diseases and pests.
options
- (A) and (R) are true and (R) is the reason for (A).
- (A) and (R) are true and (R) is not the reason for (A).
- (A) is true, but (R) is false.
- (A) is false, but (R) is true.
Assertion (A) : The rainbow is a natural spectrum of sunlight in the sky.
Reason (R) : Rainbow is formed in the sky when the sun is overhead and water droplets are also present in air.
options
- (A) and (R) are true and (R) is the reason for (A).
- (A) and (R) are true and (R) is not the reason for (A).
- (A) is true, but (R) is false.
- (A) is false, but (R) is true.
Name the type of chemical reaction in which calcium oxide reacts with water. Justify your answer by giving balanced chemical equation for the chemical reaction.