simple subject of: The cup of strawberry ice cream melted completely. is it ( ice cream). and The crinkle of a plastic wrapper being removed could be heard. is it ( wrapper)

Answer 1

No. Neither of those are subjects because they're objects of prepositions. Subjects are never in prepositional phrases.

I used to have my students put parentheses around prepositional phrases.

The cup (of strawberry ice cream) melted completely.

The crinkle (of a plastic wrapper being removed) could be heard.

Do you see what the only subjects can be now?