D. The heat is there via convection from the sun
<span> After fertilization, the </span>zygote<span> undergoes cleavage to form the blastula. The blastula, which in some species is a hollow ball of cells, undergoes a process called gastrulation, in which the three germ layers form.</span>
Covalent bonds are formed when two non metal atoms share an electron. The atoms either give up or gain an electron, due to the outer shell being unstable.
Easily can slip away from predators.
