Hey there! Let's solve the problem:
CD4 T cells activate CD8 T cells through an underhanded cycle including an antigen presenting cell (APC), customarily a standard dendritic cell (DC). An APC presents a peptide to a true CD4 T cell through a Class II MHC molecule.
B. Because a physical reaction is a change that can be seen. This particular situation is happening over a period of time, it isn’t something that happens instantly. Also I it would have been a chemical reaction, it would have mentioned something about the state of an element or the temperature or something along those lines.
