* Prefixes are added to the beginning of a word, like "un-" in "unhappy".
* Suffixes are added to the end of a word, like "-ing" in "walking".
"Survivors" is a noun formed from the verb "survive" by adding the "-ors" suffix to the root word. The "-ors" suffix turns the verb into a noun indicating a person or thing that does the action of the verb (in this case, survives).