Phytoplankton <span>are the smallest organisms in the ocean, and largely responsible for the generation of our oxygen.</span>
Amino acids are the building blocks of proteins and are made from basic amino group (−NH2) and an acidic carboxyl group (−COOH) as well an organic R group (or side chain) that is unique to each amino acid. they are made from carbon, hydrogen, oxygen and nitrogen atoms
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.
