Supercapacitor and USB


This is Arup.
1). I wanted to know the the purpose of using a supercapacitor(C26) in the ARM reference design(in the MCU. SchDoc).Is it really required even if I am using a battery?

2). There are just two ports used for USB in the ARM reference design(USB_P and USB_N), whereas usually USB requires 4 ports for communication.Can you please explain that?