Final answer:
Frog larvae have gills and tails, while adults develop legs and lungs during metamorphosis. Adults are equipped with an eardrum and lungs for terrestrial life, and their physical form is adapted for jumping and a carnivorous diet.
Step-by-step explanation:
The differences between the larval and adult stages of frogs are quite distinct. Frog larvae, often known as tadpoles, have several characteristics suited to an aquatic lifestyle, including gills for breathing, a lateral line system for sensing pressure changes, longfinned tails, and no limbs. They typically have a herbivorous, filter-feeding diet.
When they metamorphose into adult frogs, they undergo significant changes. Their gills and lateral line system disappear, and they develop limbs for movement on land. Their jaws grow larger and their digestive system evolves to accommodate a carnivorous diet. Moreover, they develop an eardrum and air-breathing lungs for life on land. The adult frogs have a short body, webbed digits, and no tail, which distinguish them from their larval stage.
Therefore, the correct answer to the differences between larval and adult stages of frogs is option a): Larvae have tails and gills; adults have legs and lungs.