"Do you know that animal?"

Translation: Znacie tamto zwierzę?

[cosmicstresshead]

Why tamto and not tamtego? Is it because zwierzę is inanimate?

[immery]

zwierzę is neuter, so there is no question of animation from grammar perspective (that is only for masculine nouns).
Neuter always has accusative=nominative.

[cosmicstresshead]

Awesome, thanks :)

[elinjen]

when should you use "zwierzeta" insted of "zwierzie"?

[Jellei]

"zwierzęta" is plural, "zwierzę" is singular.

[christiancasimir]

What is the difference between 'znasz' and 'znacie'?

[Jellei]

"znasz" is singular 'you' (Do you know that animal, Christian?), "znacie" is plural 'you' (Do you know that animal, Christian and Steven?).

Same distinction goes for any verb.