True.
Android might have a kernel derived from Linux although you should probably
be careful in calling it a “Linux”. It is not done in the spirit of
“Linux” or free software and calling it “Linux” is like like calling
Apple's Mac OS X a BSD. There may be some truth behind it although it is
completely misleading and the accuracy is a bit if not completely off.
Calling “Linux” (as a whole system) Linux is also misleading.
Android's kernel was forked and major changes were made. Until recently those
changes weren't going back into the mainline kernel. I think thats changes
now though. The rest of the system though remains heavily non-free. It's
hardly comparable to a GNU/Linux desktop system.
There have been combinations that I think would be classifiable as
“Linux” or “GNU/Linux” for hand held devices and phones. Though most
if not all of them would be utilizing at least some non-free pieces. That's
been due to the companies producing the hardware or designs closing things up
though rather than the developers of the system doing so. Android itself is
based on code that Google has not released the source code for.
