The answer is actually "to prepare for special medical needs' I took the test
An atmosphere is a layer of gas or layers of gases that envelope a planet, and is held in place by the gravity of the planetary body.
A population of squirrels is preyed on by small hawks at maturity. the smaller adult squirrels can escape into burrows. the larger adult squirrels can fight off the hawks. after several generations, the squirrels in the area tend to be very small or very large. this is an example of disruptive selection. In disruptive selection, the extreme traits i.e., very small and very large sizes are favoured over intermediate trait i.e., average size.
