The correct answers are Humans buy too many apples on Tuesdays. and There is a lot of cheese in this freezing aisle.

Apples are countable, so we use "many" and add an "-s".

Cheese is uncountable, and "a lot of" works perfectly with it.

Milk and rice are uncountable, meaning they cannot be pluralized with an "-s" (no "milks") and they must be used with "much" instead of "many" (too much rice).