but how can a license be successfully revalidated without understanding these basic questions?
Many of these questions are international issues or pilot technique . I've been a pilot since 1972 and a former ATC'er both USAF and FAA. I how no idea about o2 requirements for the UK.
Is it March Approach or March GCA? Hell, I used to work a GCA even. When I call them GCA they answer approach. When I call the approach they answer GCA?
I always leave my transponder on. The last time ATC said I was causing Ring Around... Never. GA Transponders don't have enough power.