Question

	Bones of a developing fetus develop from the:
	ectoderm. endoderm. mesoderm.

	Fertilization by more than one sperm would result in a polyploidy and an inviable zygote. What is the FIRST line of defense against polyspermy?
	species specific recognition of proteins on the outer coat of the egg changes in the membrane potential of the egg prohibiting additional sperm from entering capacitation in the sperm fertilizing the egg products released from the egg changing the zona pellucida of the egg and prohibiting additional sperm from entering

Answer 1