They are primarily responsible for maintaining and changing posture, locomotion, as well as movement of internal organs, such as the contraction of the heart and the movement of food through the digestive system via peristalsis.
Internet Users in the U.S.A. (2016*) 1  Share of U.S. Population: 88.5 % (penetration) 2  Total Population : 324,118,787. 3  Share of World Internet Users: 8.4 4  %. Internet Users in the World: 3,424,971,237.
Facebook â 72% of adult internet users/62% of entire adult population Fully 72% of online American adults use Facebook, a proportion unchanged from September 2014. Usage continues to be especially popular among online women, 77% of whom are users.