Why is the air so warm at the equator? А
Because the equator is rarely ever humid
B
Because the equator is mostly covered with water
Because the equator receives direct sunlight
D
Because the equator is closer to Earth's core

sunlight hits the Earth most directly at the Equator. The curve of the Earth means that sunlight is spread over a wider area the further you move from the Equator. Sunlight hits a smaller surface area at the Equator so heats up quickly compared to the poles.

Because the equator receives direct sunlight.