This has to do with the drivetrain of the car. In simpler terms, the power delivery system of the car. A 2wd or a two wheel drive is any general stick shift(manual transmission) car you drive. Either the front two rotates and pull your car or the back two rotates and push your car forward. For a 4wd or a four wheel drive, you can switch to all of the wheels being driven. Provides better grip on the road.
Noise-cancelling headphones. Noise-cancelling headphones are headphones that reduce unwanted ambient sounds using active noise control. This is distinct from passive headphones which, if they reduce ambient sounds at all, use techniques such as soundproofing.
When it comes to noise-cancelling headphones, there are two types to look out for: active and passive. Passive means that when the headphones are pressed against your head, some sound is cut out in the process of closing your ears off to the world outside. It's not high-tech.