Same origin policy - how to figure it out?

Question

Computer networks

Good night all.
As a non-web developer, you need to understand sop. I read a lot of information and did not understand everything. I ask to enlighten in the following questions:
SOP is implemented specifically in the browser?
SOP prevents scripts from one tab from accessing data from another tab on different domains?
If I loaded a page from test.com, this page has a script that accesses text in one of the test2.com objects, will the request be denied?
Are there objects where cross-domain interaction is allowed - script, img, video, object, frame?
XSS attacks possible by accessing another domain via script?
Thank you.