Answer is A
Firstly axon must reach the threshold level and then depolarisation occurs. Depolarisation phrase means sodium enters and potassium leaves the axon . Choice C can't be because main idea is the entering of sodium ions.
<span><span>The carboxyl end of the G- protein-coupled receptor (GPCR) is located in the cytosol (it is intracellular). Carboxyl terminus is one of the most variable structures of the protein. All of the GPCR are </span><span>structural and functional similar, unlike their ligands.</span></span>
ummm
i cant answer that question because you didn't give me the species type or what the species is