How many of the five stages of sleep are considered nrem sleep? three two four one

 During sleep, the body moves through five different stages of both REM (rapid eye movement) and NREM (non-rapid eye movement) sleep. Over the course of the night, the body will go through this five-stage cycle four to six times, spending an average of 90 minutes in each stage.

the answer is c. it will give up it's valence electron to the other atom.