Difference between "and" and "or"

Question

What is the difference between "and" and "or"?
Can we use the conjunction "or" in a positive sentence or not? How about "and"?

For example:

"Lisa likes apples and bananas."

Can I use "or" in that sentence or not? If not, why?

Answer 1

'and' provides inclusiveness. by saying "A and B", it means BOTH A and B. you may use 'and' in positive and negative sentences.

'or' provides exclusiveness between choices. by saying "A or B", it means ONLY ONE between A and B can be considered. If you choose A, then it is not B. and vice versa. you may use 'or' in positive and negative sentences.

If you say, 'Lisa likes apples or bananas.', check the context first. The speaker here [in an imagined dialogue] is not sure what Lisa likes.

Answer 2

You can you either, of course.

The difference in meaning with respect to your example is that 'and' simply expresses that Lisa likes both, in general. The use of 'or' suggests exclusivity in some special circumstances. If I were to speculate, if offered a snack, Lisa might choose apples over bananas, she also might choose bananas over apples, i.e. the choice is exclusive (for some reason). In order to select the right one, some context perhaps is called for.