Answer:
mitosis
Explanation:
Gametes are produced by mitosis (not meiosis) and after fertilization a diploid zygote is created. The single zygote cell never grows or divides my mitosis. It can only divide by meiosis to produce haploid cells once more, which then produce the main adult body.
The physical characteristics of an organism is its phenotype. I remember this because phenotype and physical both start with 'ph.'
Hope this helps. Good luck! :)
I would go with the first option
