C because the heart pumps normally with a constant pressure but when it is lower it needs to push harder to get the blood to where it needs to go causing it to malfunction
The statement that best summarizes Darwin's theory of natural selection is D. Organisms best suited to their environment will survive and reproduce. This is becasue let's say some giraffes have short necks and some long necks and their food is leaves on high trees then the long necked giraffes will survive over short necked giraffes because short necked giraffes can't reach for their food and eventually there will be only long necked giraffes left and they will reproduce with other long necked giraffes and make long necked giraffes.
Answer:
there should be about 100kj available to the secondary consumers
