What is the input of the light-dependent reactions, labeled x

In sexual reproducing animals once fertilization of the egg takes place, the exists as a single cell until cell division begins. a) egg b) larva c) sperm d) zygote

Q: a: in sexually reproducing animals, once fertilization of the egg takes place, the exists as a single cell until cell division begins

Most crimes involve some evidence relating to the human body; for that reason, what related science is frequently used in forensic investigations? a)psychiatry b)physics c)botany d)biology