Where do the sun’s rays hit earth’s surface nearly at right angles?

The Sun's rays hit Earth's surface nearly at righ angles at Equator.

Duirng March equinox and September equinox the rays fall perpendicular at Equator. During this times the duration of day light and night are nearly equal.

The Sun's rays fall perpedicular during that time because the Sun is in the sky directly over the Equator.

 

It would be the equator

The principle of independent assortment describee how different genes independently separate from one another when reproductive cells develop.