The curved paths of air movement due to the Coriolis effect are primarily caused by the Earth's rotation. Specifically, the correct statement is:
The earth spins faster at the Equator than at the poles.
This is because the Earth's diameter is larger at the Equator, so points on the Equator travel a greater distance in the same amount of time compared to points near the poles. As air travels from the high-speed rotation near the Equator to the slower rotation at the poles, it appears to curve relative to the surface of the Earth. In the Northern Hemisphere, this deflection is to the right of the direction of travel, while in the Southern Hemisphere, it is to the left.
The differing rotational speeds create a phenomenon where moving air and water are affected by the rotation of the Earth, leading to the characteristic patterns of atmospheric and oceanic circulation. This is why it is the rotation speed, not the amount of sunlight received, that is responsible for the Coriolis effect causing air to curve rather than move directly from high to low-pressure areas.