2. The endosymbiotic theory suggests that a eukaryotic cell is the result of one prokaryotic cell eating another.
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>
Answer:
I would say the second one.
Explanation:
I'm sorry if it's wrong
I would say the answer would be krill
<span> descended from land animals</span>. Scientists believed that whales have evolved 50 million years ago from land dwelling ancestors who feed on fish from nearby sea. According to unearthed fossils, the early whale's body was more adapted to land but its relatives are more suited to live in water.
