In adults, five large vertebrae fuse to form what
single structure?

teens need 8-10 hours of sleep. it kind of depends on what time you get up. but prob around 10 or 11 p.m. or 11 or 11: 30 p.m.

lifetime activities are certain actions that are either required throughout your life or you choose to do them. for example, eating is considered a lifetime activity, drinking water or other beverages, keeping your body clean, taking medicine. those types of actions are considered lifetime activities.