Question

Hens and frogs both are viviparous but they show different types of fertilisation. Why? Explain giving suitable reason

Answer 1

Hen and frog both produce eggs. However, incase of hen, the fertilisation takes place inside the body and is known as internal fertilisation while in case of frogs, the fertilisation takes place out the body known as external fertilisation.
You can also read this.
External and internal fertilization are forms of reproduction that vary in method and embryo development.

Externalfertilizationis 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).