Option 1 states that both the assertion (A) and the reason (R) are true, and R is the correct explanation of A. To determine if this option is correct, we need to evaluate the statements individually.

The assertion (A) states that all fishes have an air-bladder. A contradiction to this statement would be if there is a fish species that does not possess an air-bladder. Without further information, we cannot conclude that all fishes have an air-bladder. Therefore, A is not necessarily true.

The reason (R) states that the air-bladder helps to maintain buoyancy or aids in respiration. This statement is generally true. The air-bladder in fishes does indeed aid in maintaining buoyancy, allowing them to control their position in the water column. However, it is incorrect to state that the air-bladder aids in respiration. Fishes primarily respire through their gills, not the air-bladder. Therefore, R is not a correct explanation of A.

Option 2 states that both A and R are true, but R is not a correct explanation of A. This matches our evaluation of the statements and is the correct answer.

Option 3 states that A is true but R is false. Since A is not necessarily