joe gave a good grammar explanation- as an example: "Yes, it is a fun place to go!" - state "Yes, it does belong to her. "- action

'Is' is a form of the verb 'to be' and implies a state of being; whereas 'does', a form of the verb 'to do' implies action of some sort.

Hi. it depends on the question. For example: Is Oslo the capital of Norway? Yes, it is. Is Amsterdam the capital of France? No, it isn't. Does she work at the embassy? No, she doesn't. Does it rain a lot in your city? Yes, it does. In the first 2 examples, we use the verb 'to be'. In the last 2, we use 'work' and 'rain'. So, if we use 'to be', we say 'yes, it is/no, it isn't', but if we use any other verb in the present simple, we work with do or does. Is it clear? yes, it is does it help? yes, I think it does good luck :)