It is the strength structure of the car. Like the skeleton of the human body.
It is the frame work
Any of your examples will work the same.
It's a sub frame car.
The frame supports the vehicle. Everything bolts to the frame. The body, engine,etc...
It is either a unitized body with the frame built into the car or it is a body on frame construction. A quick look under the car will tell you which it is.
The signs are usually various scrapes or scratches.They may not look very bad but they can weaken the frame causing the car to collaps under the pressure that the damaged frame is putting on the car
A frame is the skeleton of a car without the mountings, were as a chasis is a mounted frame.
The frame work of a cell is called the cytoskeleton.
The chassis is the frame of the car.
Depends on the car front wheel drive it a cradle rear wheel drive it a sub frame.
Regardless of what any tv show or anything tells you a bent frame can be fixed as long as it is not totalled. The car will still work the same and be just as safe.
The last time I saw a truck frame under a car, i was in Poland.