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:
A.
Explanation:
The greatest risk environmentally with the unregulated harvesting, because it could endanger or terminate a species.
Answer:
It looks like a large rock with a yellowish color, and there are multiple smaller rocks inside the outer core.
Explanation: