The National Sleep Foundation says on its website, "Teens need about 8 to 10 hours of sleep each night to function best. Most teens do not get enough sleep — one study found that only 15% reported sleeping 8 1/2 hours on school nights."
The Cenozoic period began with the 65 million years ago and continuous till today and is composed of the modern-day inhabitants and is also known as the age of mammals and these were as the hornless rhinos and flight less dinosaurs.
