Which three different sources are responsible for the styles you see on the web page?

Answer 1

Looks like an high school exam question just no multiple-choice options. Lol.

It could be
1. styles defined by the browser,
2.styles defined by the user or
3.styles inherited from parent elements.
This styles can all be inspected using chrome developer tools

Answer 2

- The stylesheet created by the author of the page
- The browser's default styles
- Styles specified by the user

Answer 3

// It can be CSS or JavaScript , please make your question Much clear so community can help you.