How does genotypic variation occur?

Matthew decided he wanted to hike up mount everest. on his way to the top, it began to snow and the temperature dropped to -10°f. matthew forgot to wear a heavy jacket so his body began to shiver beyond control. in this case, matthew's body shivering is the to a drop in temperature. * 0 points reflex stimuli responce environmental facto

In which layer do organisms on earth love?

Has anyone taken the genetics unit test in connexus? not looking for answers, just a little bit what to expect and some with studying.