What is a noun in which you can add a number to the front of it and add an s at the end of it

If you were doing a report on the savannah’s of africa, which of the following websites would be your best resource

Ineed simplifying this thesis and making it easier to understand for the reader (more concise) "no matter how religious one may be, one’s faith tends to change under unexpected and challenging circumstances."

What element of medieval literature does the disappearance of the sword into the lake represent?