。
Is there a lot of food in the refrigerator?
Literal
Refrigerator [of-の] inside [in-に] many [of-の] food [subject-が] is-put-in [question-か].
A yes/no question with existential structure. 入っている ('is (in) in') uses the resulting-state ~ている of 入る (intransitive 'to enter'). たくさんの食べ物 ('a lot of food') — たくさん can modify nouns with or without の; both are accepted.