The action that is described in the question is an example of a "ligand-gated channel".
The ligand-gated channels are found in the muscles and they are membranes made out of ion-channel proteins which chan be controlled by certain released chemicals into the medium to open them up or closed them and allowing the sodium, potassium or calcium ions to pass through.
Out of the chooses given, the best description between evolution and natural selection is that natural selection leads to evolution. The correct answer is A.
