Miami preschoolers Jia Sarnicola and Zuri Copeland say they are not just best friends. In fact, Jia and Zuri truly believe they're twins. They're just 4 years old, but grown-ups could learn a lot from them. Steve Hartman reports, On The Road. Subscribe to the "CBS Evening News" Channel HERE: http://bit.ly/1S7Dhik Watch Full Episodes of the "CBS Evening News" HERE: http://cbsn.ws/23XekKA Watch the latest installment of "On the Road," only on the