Question

the time period when drivers are most at risk of driving while drowsy is between and am.

Explanation:

Based on knowledge of drowsy driving risks, the time period when drivers are most at risk of driving while drowsy is between 2 and 6 am. This is because during these early morning hours, the body's natural sleep - wake cycle (circadian rhythm) causes a dip in alertness, and many people who have been driving through the night or have disrupted sleep patterns are more likely to be drowsy.

Answer:

2 and 6