Embryo is multicellular diploid body, under mitosis it forms zygote which is single cell. The union of sperm cell and egg cell. This divides rapidly in the days followed by fertilisation. After two week of division it forms zygote. Most of flowering plants in the tissue present in the seed. It is surrounded by the embryo and also provides nutrition in the form of starch, it also have oils and proteins in it.
A chemical reaction is a process by which atoms or groups of atoms in a particular substance are rearranged from the arrangement within the reactants to a new arrangement within the products.