Answer: B
Explanation:
G protein-coupled receptors (GPCRs), also known as seven-(pass)-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptor, and G protein–linked receptors (GPLR),comprises of a large protein family of receptors that discover molecules outside the cell and initiate internal signal transduction pathways and, eventually, cellular responses. They are called seven-transmembrane receptors because they pass through the cell membrane seven times
