T cells. When HIV arrives in the lymph nodes – around 24 to 48 hours after exposure – they activate other immune cells, such as CD4 t-cells, HIV's primary target.
B. The levels of classification increased. Previously there were only 2 domains of life, Bacteria and Eukarya, but an additional domain and Kingdom were added when the distinction of Archaea was observed.
Anything can come out of that but I think type b might be more possible to happen.
Answer: Amino acids share COMMON chemical groups but have UNIQUE side chains that allow for variation. The common groups are amino and CARBOXYL groups attached to an α carbon. Amino acids link together into a polypeptide via PEPTIDE bonds. Each polypeptide has a unique sequence. The repeating subunits interact with each other via hydrogen bonds to establish secondary structures. Interactions between the side chains determine the tertiary structure of the polypeptide. The combination allows for an almost infinite number of possible structures, each with a different function.
Explanation:
