In simple terms, DHCP determines if your IP is static or dynamic and the length of time an IP address is assigned. Dynamic Host Configuration Protocol is controlled by a DHCP server. Your router can be a DHCP server...and if you're on a home network, it most likely serves this purpose.
Researchers report that the average adolescent needs eight and a half to nine and a half hours of sleep each night. But in a poll taken in 2006 by the National Sleep Foundation, less than 20 percent reported getting that much rest on school nights.
Children in preschool need 11 to 13 hours of sleep per night. Newborns sleep up to 18 hours a day, and school-aged children (up to age 12) need 10 to 11 hours. Adolescents need about nine hours of sleep a night, and most adults need seven to nine hours of sleep.