Seek to access grub on live usb install of kali sana

But I'm having difficulty finding where the grub is installed.

The reason I am trying to get to it, is to edit a line relating to the kernel and passwords, as I need to reset the root password.

QUESTIONS:
1. Is Grub in fact on the live usb version of kali 2.0?
2. how do I get to it?
3. is it possible that I never made a root password, as I don't recall being prompted for it in the install process?

thanks kindly for reading and answering these VERY basic questions