Explanation:
you just need to know that :
population density = no of ( what is asked) / land area.
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.
<span>Hope that's helpful.</span>
C) United states
it have the most greenhouse gases
Answer:
it is D because if the parasite feeds on blood not enough blood will make the hosts heart no pump enough blood and eventually die