C as activation energy is the highest curve on the graph
Answer:
peptide antigens by MHC class II molecules
Explanation:
Helper T cells are activated by peptide antigens by MHC class II molecules. These antigens express on the surface of antigen-presenting cells (APCs). After activation, the T helper cells divide and secrete cytokines to assist the immune response.
Answer:
Plant cells have a large central vacuole, a cell wall, and chloroplasts while animal cells do not.
Hope this helps!
I’m not sure how to answer your question if there is no link to the video?
Diffusion has a major part in this. It has proteins embedded in it that allow molecules to diffuse in and out of the cell up and down its concentration gradient.