Final answer:
A tadpole's transition to an adult frog involves the loss of its gills and tail, development of limbs, a larger jaw, a short digestive system, and the emergence of lungs and an eardrum.
Step-by-step explanation:
A tadpole undergoes several changes to develop into a frog. Initially, tadpoles have gills, longfinned tails, and lack limbs, which are adapted to an aquatic lifestyle. As they enter metamorphosis, the tadpole's gills and lateral line system disappear, and they begin to develop four limbs.
The hinder limbs grow first and become powerful, preparing the frog for jumping. The tail recedes, the jaws become larger, adapted to a carnivorous diet, and the digestive system shortens, becoming more efficient for a predatory lifestyle. Further, the development of an eardrum and air-breathing lungs takes place. These changes facilitate the transition from water to land-based existence as the adult frog.