You have to change the front-right wheel of your biaxial motor vehicle. You apply a wheel chock to prevent the vehicle from accidentally rolling off. What must you be aware of when doing so?

The selected combination of answers is correct because both points address essential safety measures when changing a wheel on a motor vehicle.

1. Placing the vehicle on the most stable ground possible is vital to prevent it from rolling and causing injury or damage. This aligns with German traffic rules that emphasize the importance of safety during vehicle maintenance.

2. Utilizing a wheel on the rear axle as a chock helps secure the vehicle against unexpected movement. This is also a recognized practice in vehicle maintenance, contributing to a safer working environment.

Both steps are crucial to ensuring your safety and the integrity of the vehicle while you perform the tire change. Choosing only one or overlooking these measures could lead to accidents or injuries, which is why it's necessary to consider all relevant options.