Why is the id used only once

Answer 1

The id is used to identify exactly 1 html object in the DOM.
If you want to address multiple html objects, you can refer to them by class or by tag name.

Answer 2

It means only one id can be assigned to a element as id is a unique name given to any tag/elements.
So there can’t be more than one id to an element.

Answer 3

Your answer is in my question.

https://www.sololearn.com/discuss/1713785/?ref=app