I believe the answer is B.
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.
Here's some tips that should help: All cells, both prokaryotic and eukaryotic, have genetic information in the form of DNA. They also have ribosomes that translate genetic information into proteins. All cells also have a cell membrane that protects the contents of the cells. Inside the membrane, all cells have a gel-like substance known as the cytoplasm.
DNA is the correct answer
The exchange takes place in the millions of alveoli in the lungs and the capillaries that envelop them. inhaled oxygen moves from the alveoli to the blood in the capillaries, and carbon dioxide moves from the blood in the capillaries to the air in the alveoli.