What do biologist use to establish whether or not two organisms are of the same species

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

The first signs of cellular differentiation occur in the blastocyst. why is cellular differentiation important for the development of a fully formed human infant?

In what part of a chloroplast does glucose production occur? a. atp synthase b. photosystem ii c. photosystem d. stroma