Why is it required to drive in low gear on a steep descent?

1. To save fuel and to reduce engine wear.
2. Correct answer: To use the engines compression in order to maintain a slow and constant driving speed without overusing the brakes.
3. To prevent tire wear.
4. To prevent overheating of the vehicle’s engine.

WhyIn a low gear the engine holds the speed, so you do not have to press the brakes constantly. That way they do not overheat.