The answer is fusion of gametes via fertilization.
Functions of cell surface Receptors .
most ligands responsible for cell-cell signaling ( including neurotransmitters, peptide, hormones, and growth factors) bind to receptors on the surface of their target cells.
Lettuce, strawberries, peppers, corn, squash
What is A B C and D? You have to tell us what the options are so we can answer.
If going to be the first one home boy