Define the following terms:
$(1)$ Spermiogenesis
$(2)$ Zona pellucida

(N/A) $(1)$ Spermiogenesis: The process by which spermatids are transformed into mature spermatozoa is known as spermiogenesis.
$(2)$ Zona pellucida: It is a thick,transparent,non-cellular glycoprotein layer that surrounds the plasma membrane of the secondary oocyte.