<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.
Answer:
DNA:
Dexoyribonucleic acid is the genetic material of almost all the organisms except some virus. DNA contains deoxyribose sugar that lacks 2'OH group on second carbon. The nitrogenous base pair of DNA are adenine, guanine, thymine and cytosine. DNA cannot acts as an enzyme.
RNA:
Ribonucleic acid is present as genetic material in few viruses only. RNA contains oxyribose sugar that has 2'OH group at second position. The nitrogenous base pair of RNA are adenine, guanine, uracil and cytosine. RNA can acts as any enzyme in biological reactions.
Answer:
The correct answer is:
Includes at least two groups, one of which does not receive the experimental treatment. (B)
Explanation:
A controlled experiment is made up of at least two groups of participants (subjects). One group (the test group) receives the experimental treatment, which can be an intervention or a new drug to be tested etc, and the effect of the treatment on the subjects is measured, while the second group of similar subjects also known as the control group acts as a baseline and do not receive the treatment or intervention. They act as a baseline to ensure that the change observed in the treatment group was brought about as a result of the treatment.
<em>Note that repeating the experiment several times does not ensure accuracy of the result, rather it ensures reliability of the results hence option D is not correct</em>
Answer:
1,2 and four
Explanation:
over fishing would cause loss of every species
