Which of the following cannot be composted?
banana peel
meat
grass clippings
leaves

Meat is the only one of the above answers that cannot be composted.

Explanation:

Meat is something that can be composted but it can easily bring maggots and flies. It can also bring cats and dogs. It also slows down the composting process.

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."