Which one of the following statements is correct?

The correct statement is that tadpoles have gills. Tadpoles represent the aquatic larval stage of amphibians and utilize gills for respiration [c4, t9]. In contrast, adult frogs transition to using lungs and skin [c4]. Statement 1 is incorrect because fishes exhibit diverse feeding habits, including herbivorous, omnivorous, and carnivorous diets [t2, t3]. Statement 2 is incorrect because while adult amphibians have three-chambered hearts [t9], tadpoles initially possess a two-chambered heart similar to fish, which later develops into the three-chambered structure during metamorphosis. Statement 3 is incorrect because not all fishes possess swim bladders; for instance, cartilaginous fishes like sharks lack them and rely on other mechanisms for buoyancy. Therefore, the presence of gills in tadpoles is the only universally accurate statement among the options provided [c4, t7].

Sources

1. [1] Science-Class VII . NCERT(Revised ed 2025) > Chapter 9: Life Processes in Animals > 9.2.2 Do other animals breathe the same way as humans do? > p. 133
2. [2] https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/metynnis