Answer:
External fertilization is characterized by the release of both sperm and eggs into an external environment; sperm will fertilize the egg outside of the organism, as seen in spawning.
Internal fertilization is characterized by sperm fertilizing the egg within the female; the three methods include: oviparity (egg laid outside female body), ovoviparity (egg held within female), and viviparity (development within female followed by live birth).
Internal fertilization protects the fertilized egg or embryo from predation and harsh environments, which results in higher survival rates than can occur with external fertilization.
Ovoviparity is characterized by an organism retaining a fertilized egg inside the body where development occurs and nourishment is received from the yolk.
Viparity is characterized by an organism which has its young develop within the female and nourishment is received directly from the mother via a placenta.
oviparous: egg-laying; depositing eggs that develop and hatch outside the body as a reproductive strategy
viviparous: being born alive, as are most mammals, some reptiles, and a few fish (as opposed to being laid as an egg)
ovoviparity: eggs are retained in the female, but the embryo obtains its nourishment from the egg’s yolk
