Unicellular organism ...................................................................................................
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.
A zygote is immediately formed after fertilization between two gametes. This cell is eukaryotic and made up of a combination of the DNA in both gamete. Zygote contains all the hereditary information essential in the formation of a new individual.
<span>The MOSQUITO spreads more parasitic diseases to humans than any other vector.
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Energy stored in food can be used by cells to add a phosphate group to ADP to make ATP. This cycling of ATP to ADP occurs in a metabolic process called cellular respiration. phosphate group breaks, and energy is released. ATP becomes ADP, and the cycle of storing and releasing energy continues until the cell dies.