Describe the importance of an intromittent organ (penis) in males for terrestrial reproduction. Compare and contrast the female reproductive system...

Describe the importance of an intromittent organ (penis) in males for terrestrial reproduction. 

Compare and contrast the female reproductive system of amphibians and monotremes. In what ways are reptiles intermediate?

What is the difference between a cloaca and a vulva? Why would a vulva be preferable for live birth?