please help

[Unregistered]

hello,
which is correct:

1. American army helicopter
2. America's army helicopter

and what's the meaning of heterogenous stones?

thanks

 

[Anglika]

#1 American army helicopter.

#2 What's the meaning of heterogenous stones? What is the context? It is a term used in urology relating to the nature of kidney stones. It is also a term found in geology.