In teen friendships, teens often have close, non-sexual friendships with teens from the other gender peers are typically more harmful than a well-behaved teen is often friends with a deviant teen friends lure each other into self-destructive behavior

I believe the answer is:  teens often have close, non-sexual friendships with teens

Unlike what has been depicted by Hollywood, the vast majority of Teen friendships are actually non-sexual in nature.
On average, people become sexually active when we're entering young adulthood phase (18 years of age or older) 

It could be anything, recent improvements in technology/telecommunication/internet have increased the pace of globalization.generally, it has something to do with technology. globalization means that people around the world are brought together through technology which speeds things up. so maybe some of those options could be correct. : )