Question

a t helper cell becomes activated by a(n) __________. multiple choice plasma cell antigen presenting cell b cell memory cell mast cell

Explanation:

T helper cells are activated by antigen - presenting cells (APCs). APCs, such as dendritic cells, macrophages, and B cells (in some cases), present antigens in the context of MHC (major histocompatibility complex) molecules. When a T helper cell recognizes the antigen - MHC complex on an APC, it becomes activated. Plasma cells are antibody - secreting cells derived from B cells. B cells can act as APCs in some situations but are not the most general or typical activator of T helper cells in the initial sense. Memory cells are long - lived cells that "remember" an antigen for a faster immune response upon re - exposure. Mast cells are involved in allergic reactions and innate immunity, releasing histamine and other mediators.

Answer:

antigen presenting cell