A compact SUV works through the same main vehicle systems as other passenger vehicles: a structure supports people and equipment, a powertrain supplies movement, suspension and steering manage the wheels, and brakes reduce speed. Its defining feature is the way those systems are packaged into a relatively small SUV body.
Compact does not identify a single engine, drive layout, or chassis design. A model may use gasoline, hybrid, plug-in hybrid, or battery-electric propulsion, with front-wheel drive or another driven-wheel arrangement. Understanding the actual system explains more than assuming every compact SUV operates like a scaled-down truck.