Consider the cell cycle; which stage takes pretty much the same amount of time regardless of cell type? explain

The correct answer would be mitosis or M phase.

Mitosis or M phase is the phase of the cell cycle during which the actual division of the cell takes place that is, the division of nuclear content. It is also termed as karyokinesis.

It is primarily divided into four stages:

It results in the equal distribution of  chromosomes into two daughter cells.

It is followed by cytokinesis by which cytoplasmic content is equally divided into the two daughter cells.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).