Plz help answer all 4 question!!

What happens after a star goes supernova? just wondering! [tex]supernova [/tex] answer asap i really wanna know!

Francine, a college freshman, has agreed to participate in a psychology research study. before she begins her participation, she reads a statement written by the researcher explaining the purpose of the research and the potential risks of participation. it also explains that francine is free to withdraw from the research at any time. in providing francine with this statement, the researcher has followed the ethical guidelines of for participants.

The middle east has very limited fresh water sources in the form of rivers such as the nile, jordan, euphrates, and tigris rivers. however, these rivers are only located in a few countries. which country does not have one of these rivers within its borders?