I am a bit confused about "zvíře" gender. In Tips and Notes of neuter form, it is said that "zvíře" ¨is masculine. But actually, it is presented in the neuter section, and this exercise translates "Good animal" as "Dobré zvíře", which I guess it is neuter. In some later exercise of "To be pl." section, "They are animals is translated as "Oni jsou zvířata.", which I guess it is masculine. So, what is the matter here? Is it singular masculine or neuter? Does it change gender from singular to plural? Thank you.
Zvíře is indeed neuter.
The tips & notes sections actually states that pretty clearly: 'Some nouns that end in -e are masculine, e.g., soudce (judge), or neuter, e.g., děvče (girl), zvíře (animal).'
Oni jsou zvířata. means 'They (the men/the boys/the tigers/the lions/any masc animate) are (like) animals.'