Answer:
The major functions of the circulatory system is it delievers oxygen and nutrients to cells and takes away wastes.
Explanation:
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<span>Cytotoxic t-cell subpopulations are specialized to combat intracellular pathogens, whereas helper t-cell subpopulations are specialized to combat extracellular pathogens.
</span>Cytotoxic t-cell are CD8+ cells. Cytotoxic t-cell uses granzymes to <span>kill </span><span>intracellular bacteria, that lives in the cytosol such as viruses. They identify the pathogen forgein peptids that are bounded to MHC-I on the cell surface.
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cd4+ T helper (Th) cells include Th1, Th2, and Th17 cells. They contribute to aliergic reactions and fighting extracellular parasites.
<span>An environmental factor that causes a population to decrease is death</span>
That is false The higher the elevation, the faster the weathering will occur.
The number of workers for each person receiving Social Security benefits is called the DEPENDENCY RATIO. An increase in the dependency ratio increases the burden on the productive part of the population and has a direct direct impact on financial expenditures on things like <span>social security.</span>
