Answer the following question given this paragraph: 

Amphibians have moist skin without scales. The skin is kept moist by mucus, which is secreted by mucous glands. In some species, the mucous glands also secrete toxins that make the animal poisonous to predators. The blue poison-dart frogs in Figure below are a good example. The toxin in their mucus is used by native people in South America to poison the tips of their hunting arrows.


Q: Which group of species is defined as having moist skin without scales?

 Choices:

- fish

- mammals

- reptiles

- amphibians

A:
amphibians
