The tropical cyclones do not occur to the equator because of

weak coriolis force
light and variable width
excessive humidity
connective activity

The correct answer is: A. weak coriolis force.

The Coriolis force is an apparent force that deflects objects moving in a straight line on a rotating object. The strength of the Coriolis force depends on the latitude, with the force being strongest at the poles and weakest at the equator.

Tropical cyclones are large, rotating storms that form over warm waters near the equator. The Coriolis force is necessary for tropical cyclones to form, as it helps to create the spin that is necessary for the storm to grow. However, the Coriolis force is very weak at the equator, which is why tropical cyclones do not occur there.

The other options are incorrect for the following reasons:

  • Option B: The width of a tropical cyclone is not related to the Coriolis force.
  • Option C: Excessive humidity is not necessary for tropical cyclones to form.
  • Option D: Connective activity is not a factor that affects the formation of tropical cyclones.