What is the test for showing only the knowledge or awareness of a gun's presence (a sub-element of possession) in a possession case?

Accordingly, showing only the defendant's knowledge or awareness of a gun's presence (a sub-element of possession) would also be insufficient to sustain a guilty verdict. We have further held that "the government must do more than show that the defendant was present as a passenger in the vehicle and within reach of the weapon." United States v. Behanna, 814 F.2d 1318, 1320 (9th Cir.1987). Evidence revealing the "mere proximity of a weapon to a passenger in a car" will not suffice to sustain a conviction. Soto, 779 F.2d at 560.