Question

¿Qué clases de animales existen en este planeta?

Answer 1

Mamiferos = mammals
Peces = fishes
Insectos = insects
Reptiles = Reptiles
Pajaros = birds

Answer 2

Answer:

The right option to the question: ¿Qué clases de animales existen en este planeta? is:

• En este planeta existen toda clase de animales.

Explanation:

The translation of the sentence is:

• On this planet exist all kinds of animals.

The verb "existir" in Present Tense has the next conjugations depending of the personal pronouns:

• Yo existo.
• Tú existes.
• Él existe.
• Ella existe.
• Ello existe.
• Nosotros existimos.
• Ellos existen.

The noun within the sentence, that is, who performs the action, are "all kinds of animals" that could be replaced by the personal pronoun "ellos" or "they" in English, so, the right conjugated form of the verb "existir" that applies is "existen".