The largest unit within which gene flow can readily occur is a
a. population c. genus.
b. species d. hybrid.

a. population

Explanation:

Gene flow cannot occur in hybrids because 99.9% of the time hybrids offspring are not fertile.

At genus level is not possible either because a hybrid is a cross breed at the genus level (horse-donkey).

A population is a group of species of 1 kind. A population of donkeys.

one part of the electromagnetic spectrum that arrives on earth as solar radiation from the sun is the visible spectrum. wavelengths of the visible spectrum combine to form what we refer to as

answer - d) ultraviolet radiation.

violet /   380–450 nm / 668–789 thz

violet is number 1 in the chart of visible light.