The countercurrent heat exchanger that prevents arterial blood from overheating the testes is the pampiniform plexus of veins. The pampiniform plexus helps to regulate testicular temperature, allowing sperm maturation. It surrounds the testicular arteries and works as a countercurrent heat-exchanger system to cool the arterial blood before entering the testes. This is because the sperms can not develop if the testis is at body temperature.
I’m guessing it’s probably A or C
Nutrients cross the membrane wall with the help of protein channels.
most of a atoms mass is in the nucleus of the atom:) hope this helps you
ATMOSPHERE LAYERS: Troposphere, Stratosphere, Mesosphere and Thermosphere
hope this helped :) pls give brainiest