What are the two elements of meiosis that add variation to our population?

(Hint: one occurs in prophase I and the other in metaphase I).

The correct answer to this question is this:

In stage of prophase crossing-over (the physical exchange of chromosome parts) occurs. Crossing-over is the process that can give rise to genetic recombination.

In mataphase stage Independent assortment is occour and it refers to the random arrangement of pairs of chromosomes. The diagram below shows four possible arrangements of chromosomes during metaphase 1 from an individual that has 6 total chromosomes. Suppose that the pink chromosomes are those that the individual inherited from its mother and the blue colored ones were inherited from its father. For each chromosome pair, the chromosome that is on the left (maternal or paternal) is determined randomly. As can be seen, there are several alignment possibilities.