Answer:
Reciprocal altruism is one of the altruism behaviors in which an individual organism helps in increasing the fitness of another organism by reducing the fitness of itself temporarily in expectation of the same behavior from another organism in the future later.
It takes place in the same set of organism partners which is a continuous interaction ion in stable groups of organisms.
Thus, the correct answer would be - an ongoing interaction in the same set of partners.
DNA is the ultimate control of cell's productions. So A.
The answer is A, Viruses
Viruses cannot reproduce on their own , so they have to inject their DNA or RNA into the nucleuus of a cell. By doing this, the virus will take over that cells and within times, that cells will pop up and producing more viruses.
This reproduced virus will repeat the same process until our immune systems stop them