Final answer:
To protect oneself in a convoy under combat conditions, maintaining a safe distance between vehicles is the best practice, while also avoiding high speeds and keeping vehicle lights off to prevent becoming an easier target.
Step-by-step explanation:
The best practice to protect yourself in a convoy under combat conditions is to maintain a safe distance between vehicles. This helps to prevent collisions and provides enough reaction time if one vehicle is targeted or hits an explosive device, thereby minimizing the potential for a chain reaction that could harm several vehicles. Driving at high speeds or keeping all vehicle lights on could make the convoy more noticeable and hence a bigger target. Traveling in a single file could be advantageous in certain scenarios but does not inherently provide protection. Instead, the focus should be on maintaining safe distances, keeping lights off to avoid detection, and making use of strategies such as varying the convoy's speed and route to be less predictable.