Question

you notice that you and your siblings look alike in some ways, but are very different in other ways. one of your brothers has freckles, but you and your other siblings do not. your sister has blonde hair while the rest of you have brown hair. all of you have brown eyes. there are several things that account for the genetic variation between related individuals. look at the diagram. what is happening in the green circle marked “a” and what impact does it have on genetic variation?
a
recombination or “crossing over” is occurring which increases genetic combinations in the gametes.
b
recombination or “crossing over” is occurring which decreases genetic combinations in the gametes.
c
mutations occurred which changed the genes in the chromosomes, resulting in gametes that are identical.
d
mutations occurred which changed the genes in the chromosomes, resulting in more genetic diversity in the offspring.

Explanation:

The green circle (A) in the meiosis diagram represents crossing over (recombination) during meiosis I. Recombination (crossing over) increases genetic diversity by creating new combinations of alleles in gametes. Option A states "Recombination or 'crossing over' is occurring which increases genetic combinations in the gametes", which matches the process of crossing over increasing genetic variation. Option B says it decreases combinations (incorrect), C and D involve mutations (not shown here, as crossing over is recombination, not mutation).

Answer:

A. Recombination or "crossing over" is occurring which increases genetic combinations in the gametes