All tetrapods are vertebrates (and so are their fishy ancestors). Amphibians, reptiles, and mammals are tetrapods (which means they have four limbs, or at least their ancestors did). Mammals are the only tetrapod clade with hair. Birds are the only tetrapod clade with feathers. Anurans (frogs and toads) are the only amphibian clade without tails.
The Correct Answer and Explanation is:
The statement that “All tetrapods are vertebrates (and so are their fishy ancestors)” is true. Tetrapods, including amphibians, reptiles, birds, and mammals, all belong to the superclass Tetrapoda within the subphylum Vertebrata, meaning they are vertebrates. Their common ancestors were fish, and through a process of evolution, certain fish species adapted to life on land, leading to the emergence of tetrapods.
Tetrapods are defined by having four limbs (or, at the very least, having ancestors that did). These limbs are used for terrestrial locomotion. The development of tetrapods from fish is an essential evolutionary transition, marked by the appearance of limbs from the fins of ancestral fish, facilitating movement on land.
Mammals, as a unique group within the tetrapods, are the only clade to possess hair, which serves various functions, including insulation, protection, and sensory roles. Hair is a distinctive feature of mammals and is absent in other tetrapod groups.
Birds, while also tetrapods, are distinguished by the presence of feathers, a characteristic that no other tetrapod group shares. Feathers, which likely evolved from scales, have a variety of roles in birds, including flight, insulation, and communication.
The statement about Anurans (frogs and toads) being the only amphibians without tails is also correct. Adult members of the Anura order (frogs and toads) undergo a transformation during development where their tail is resorbed. This is in contrast to other amphibians, like salamanders, which retain their tails throughout their life. The absence of a tail in adult frogs and toads is a key identifying feature of this group.
