<prompt> What is the function of zona pellucida?Prevent wrong implantation of embryoFormation of blastocystPrevention of multiple sperm entryPrevent wrong attachment of sperm  <response>: Ans. C. Prevention of multiple sperm entry Zona pellucida is a glycoprotein layer surrounding the membrane of oocytes. Once sperms reach ova, there is release of hyaluronidase - penetration of corona radiata and cumulus cells by sperm. Glycoproteins on the outer surface of the sperm then bind with glycoproteins on the zona pellucida of the ovum. Zona reaction: Once sperm penetrates zona pellucida, the ovum become impermeable to other sperms, this prevents polyspermy. 