Helper T cells <span>are required for almost all </span>adaptive immune responses<span>. They not only help activate B </span>cells to<span> secrete antibodies and macrophages </span>to<span> destroy ingested microbes, but they also help activate cytotoxic </span>T cells to<span> kill infected target </span>cells<span>.</span>
The picture is not comming up
If all humans had the same DNA, and one person got the cold, everyone would die at some point. The more diversity there is the more chance of surviving an outbreak or natural disaster or something. Think of the flu. there are HUNDREDS of strains out there. some are resistant to our medicines and others aren't.
Answer:
D. Enzymes open the DNA strand, remove a segment of DNA from the strand that contains the damage, and resynthesize the correct DNA sequence.
Explanation:
From time to time, the DNA gets exposed to certain chemicals or radiation that damages it. However, the cell has a DNA repair mechanism in place called NUCLEOTIDE EXCISION REPAIR (NER).
NUCLEOTIDE EXCISION REPAIR (NER) is one of the DNA repair mechanisms in which certain enzymes open the DNA strand, remove a segment of DNA that contains the damaged gene or nucleotide bases, and resynthesize the correct DNA sequence using the pair of the damaged one.
