The correct option is A.
An infection disease is a type of disease which a person can acquire as a result of contact with the person who has the disease or as a result of contact with body fluids from that person. Infectious disease can be spread through increased virulence, increased incidence and different portals of entry. A decreased transmissibility reduces the probability of an infectious organism been transmitted.
Amino acids that are also called proteins
I believe the correct answer is that The genetic variation between humans and orangutans is the greatest.
We cannot say that there is no genetic variation at all, because there obviously is - we are not the same as the other three apes, even though we have a common ancestor. Also, we cannot say that we are completely the same, because there are obvious differences. And finally, we didn't originate from those three animals, but rather all of us come from the same organism.