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.
the answer would be A Do not run out because they are renewable
Answer:
algae - crown pls
Explanation:
algae because if there wasnt algae the food chain wouldnt survive
The answer is true for both 13 and 14. im not positive but i have just recently gone over this.
Answer:
False
Explanation:
the amount of neutrons in an atom can vary, which is why we have different types like uranium 242 and 243 etc. regarding how many neutrons it has, some hydrogen have no neutrons as well.
