Sleep apnea is a disorder characterized by pauses in breathing during sleep. children who suffer from untreated sleep apnea often have behaivor problems

Hyperactivity
Decrease in school performance 
Developmental and growth problem 
sleep apnea  is a sleeping  disorder that is characterized by pauses in breathing during sleep. The pauses experienced during sleep apnea can last for a few seconds to a few minutes and it usually happen many times in the night. Thus, sleep apnea disrupts normal sleep and those affected might tiredness during the day. This disorder causes hyperactivity, decrease in school performance and developmental and growth problem in children.

C) to ensure each new cell has an exact copy of the dna