Presence of gills in the tadpole of frog indicates that:
Presence of gills in the tadpole of frog indicates that:
fishes were amphibious in the past
fishes evolved from frog-like ancestors
frogs will have gills in future
frogs evolved from gilled ancestors.
Solution
Tadpoles are the larval forms of frog and toads. They respire through gills whereas the adult form respire through the skin and lungs. Since, fishes also respires through gills. Hence, presence of gills in the tadpole indicates that frogs are evolved from gilled ancestors.
Related Theory
"Ontogeny recapitulates phylogeny" mean that the development of individual organisms (ontogeny) follows (recapitulates) the same phases of the evolution of larger ancestral groups of related organisms (phylogeny).