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.
B. some species die out when environmental changes occur
3A)Amino acids-peptide
3B)Enzymes–speed up
3C)Active sites–substrate
3D)Unchanged
3E)[follow the instructions given]
4A)DNA—RNA
4B)Nucleotide—Deoxyribose–Phosphate–Nitrogen base
4C)DNA
4D)Thymine–Adenine—Cytosine–Guanine
4E)Hydrogen bonds
I wpupd say D but im not sure
B.Sometimes true,As you sometimes to need to learn on the alternative provided in getting a solution that is factual
