The word mice is a noun. It is the plural form of the word mouse.
Yes, mice do eat grass as part of their diet.
No, mice are not commonly eaten as part of a human diet.
part of speech
The part of speech for this particular word is a noun.
The part of speech for "answer" is a noun.
adverb
what part of speech is beneath
they are predators of mice. mice are part of their main diet
The part of speech for "explicit" is an adjective.
The part of speech for "twirl" is a verb.
The part of speech for "unfamiliar" is an adjective.
The part of speech of "came" is a verb.