Answer: mercury (i think)
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.
Ribosomes, because both prokaryotes and eukaryotes have ribosomes to make proteins.
Answer: when their is a new moon
Explanation: