The correct option to fill the sentence in Spanish, taking into account the class of animal is:
- un mamífero
- El delfín es un mamífero.
What is a Mammal?
Mammals are the different classes that animals have, which is characterized by animals whose gestation occurs within the womb of their mother, they are warm-blooded and breathe through the lungs.
In the case of dolphins, because they are marine animals, they tend to be thought of as fish, however, since these animals carry out all the previously mentioned activities, it is pointed out that they are mammals.
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