Free Response

Explain why frogs are restricted to a moist environment.


A moist environment is required, as frog eggs lack a shell and dehydrate quickly in dry environments.

Describe the differences between the larval and adult stages of frogs.


The larval stage of frogs is the tadpole, which is usually a filter-feeding herbivore. Tadpoles usually have gills, a lateral line system, long-finned tails, and lack limbs. In the adult form, the gills and lateral line system disappear, and four limbs develop. The jaws grow larger, suitable for carnivorous feeding, and the digestive system transforms into the typical short gut of a predator. An eardrum and air-breathing lungs also develop.