Answer:
The correct answer is D. proliferation and differentiation.
Explanation:
Primary immune response occurs due to the first exposure of an antigen to the immune system. The primary immune response is generally delayed by many days because it takes time for B and T cells to become cloned and to proliferate and differentiate.
Then after several days of proliferation and differentiation of activated T and B cells, T cells become effector T cells and B cell becomes plasma cells which then eliminates the antigen. Memory B and T cells are also produced during this process which helps in generating a quick immune response during the second and subsequent exposure of that antigen.
So the correct answer is D. proliferation and differentiation.
Which 2 species? like I need to know in order to tell you
Crossing over occurs but on in meiosis 1
Because it's vital to the survival of all species, not just human, that we have resources such as food and water. Also that those resources be clean and healthy. We also need to manage resources such as oil to make sure there are fewer wars like the ones happening in the Middle East. If you need anything else just message me.