The answer is bioaccumulation. Bioaccumulation is when toxins build up in a food chain. The animals at the top of the food chain are affected most severely because the concentration of toxin becomes most concentrated in the body tissues of the animals at the top of the food chain.
Answer:
Helper T cells are arguably the most important cells in adaptive immunity, as they are required for almost all adaptive immune responses. They not only help activate B cells to secrete antibodies and macrophages to destroy ingested microbes, but they also help activate cytotoxic T cells to kill infected target cells.
Explanation:
Helper T cells become activated when they are presented with peptide antigens by MHC class II molecules, which are expressed on the surface of antigen-presenting cells (APCs). Once activated, they divide rapidly and secrete cytokines that regulate or assist the immune response.
