Which of the following lacks a digestive tract?
a) a shark.
b) a tapeworm.
c) a snail.
d) an earthworm.

Asquirrel population lives in an area. over many years, a river in that area grows wider and stronger, eventually forming a canyon. the squirrel populations on the two sides of the canyon can no longer mate with each other and ultimately form distinct species. this is an example of

Several billion years ago which gas was the least prevailant in the atmosphere

Several bodily responses are described below. for each response, determine what caused the change in homeostasis. body starts to sweat breathing rate increases amount of saliva produced changes body starts to shiver