Someone explain question number 4
please !!!

The passage suggests that if on a certain day the wind were to decrease until there was no wind at all, which of the following would occur?
(A) The air closest to the ocean surface would become saturated with water vapor. - Correct Answer-
But the differences, however small, are crucial, and the disequilibrium is maintained by air near the surface mixing with air higher up, which is typically appreciably cooler and lower in water-vapor content. - Means that air is helping to maintain the disequilibrium and lack of this will have the stated effect.
Also, rest of the answer choices is irrelevant. Using POE.

(B) The air closest to the ocean surface would be warmer than the water.
(C) The amount of moisture in the air closest to the ocean surface would decrease.
(D) The rate of heat and moisture transfer would increase.
(E) The air closest to the ocean would be at the same temperature as air higher up.

Hi Anshuman

Q4 asks: The passage suggests that if on a certain day the wind were to decrease until there was no wind at all, which of the following would occur?

Before answering this question, let us examine what the passage says about wind. According to the passage, the wind plays two roles:

i) "The air is mixed by means of turbulence that depends on the wind for its energy". What is this "mixing" that is spoken about here? The answer lies in the previous two sentences: " Within about a millimeter of the water, air temperature is close to that of the surface water, and the air is nearly saturated with water vapor. But the differences, however small, are crucial, and the disequilibrium is maintained by air near the surface mixing with air higher up, which is typically appreciably cooler and lower in water-vapor content".

Therefore, we can surmise that there is a disequilibrium due to which the air near the surface is only "nearly" saturated (as evidenced by the words "the differences, however small, are crucial"). This disequilibrium is maintained by turbulence caused by the wind.

ii) "An interacting-and complicating-phenomenon is wind-to-water transfer of momentum that occurs when waves are formed".

The correct answer has to therefore negate one fo the above two phenomena.

(A) The air closest to the ocean surface would become saturated with water vapor. Correct - it negates (i) above. Water is no longer "nearly" saturated but fully saturated.

(B) The air closest to the ocean surface would be warmer than the water. Wind is not shown to impact temperature. Eliminate.

(C) The amount of moisture in the air closest to the ocean surface would decrease. Incorrect - the opposite would happen as discussed above. Eliminate.

(D) The rate of heat and moisture transfer would increase. Incorrect - the opposite would happen to moisture transfer as discussed above, while we know nothing about heat transfer. Eliminate.

(E) The air closest to the ocean would be at the same temperature as air higher up. Wind is not shown to impact temperature. Eliminate.

Hope this helps.
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