After the macrophage fails the Helper T Cell stimulates the B cells (create antibodies) if pathogen is extracellular and Cytotoxic T Cells (killer T cells, release perforin) if pathogen is intracellular. Once the pathogen is killed the B Cells create Memory B Cells and the Killer T Cells create memory T Cells.
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Answer:
D: Both B and C
Explanation:
The process is never linear, scientists often answer a question that then leads to another one, therefore B is correct. C is also correct because hypotheses often change after an experiment has been done, and the goal of science is to constantly find more accurate information.
