I like fruit
Here, fruit refes to a category called fruit. that's why we use singular form:fruit.
I like oranges and apples.
oranges and apples refer to two kinds of fruit.
I have oranges and apples. I mean I have two fruits.
Here, we can use plural form of fruit because it refers to kinds of fruit not a category.
I eat a piece of fruit every morning.
Here, piece refers to ,not kind or category, but one component. it could be an apple or a orange.
I eat an apple every morning.
I think it is right.
I eat a piece of an apple.
We would not say like this because we usually use "piece" when we refer to a component of a category not kind. it implies that we split an apple, then I eat one of them
What I understand so far is that
A category consist of kinds and each kind consists of components.
when we refer to a category using fruit, we have to use singular form.
but we can use plural form when we refer to kinds with a categorical noun "fruit"
Am I right to think this way?.