Which control can make the climate of a high plateau cooler than nearby plains?

Correct answer: Altitude

The direct answer is option A: altitude can make a high plateau cooler than nearby plains. A plateau is elevated land with a relatively level surface. Its height above sea level matters more for this comparison than the shape of its surface. Since temperature generally decreases with increasing altitude, a high plateau may be cooler than a low plain nearby, even when both are in the same broad region. Option A is correct because it is the relevant climatic control. Option B is wrong because sea depth does not directly explain the temperature of an inland high plateau. Option C is wrong because population size does not control air temperature. Option D is wrong because crop type may reflect climate or land use, but it does not cause the plateau’s lower temperature. Other controls may also operate, yet altitude is the best answer among the choices. Memory cue: high plateau means think height first.