Answer:
The egg is covered in a thick outer coating known as the zona pellucida, a layer of carbohydrate-covered proteins that surrounds the plasma membrane. The zona pellucida helps protect the egg and is responsible for mediating the initial meeting of sperm and egg.
An egg changes dramatically at fertilization. These changes include its developmental potential, its physiology, its gene expression profile, and its cell surface. ... We highlight the major cell surface changes that occur in echinoderms, one of Just's preferred research organisms.
Step-by-step explanation: