sentence: Tadpoles have tails and gills.
sentences_before: Frogs can live on land and in fresh water. They cannot survive in salt water. Their development is by metamorphosis. They hatch as tadpoles  from eggs, which are laid by a female frog. The eggs are called frogspawn.
sentences_after: When they grow up, they lose their tails and gills and grow four long legs.
concept_name: tadpole
headings: Frog