What must be true about a Marine's feet when recording their weight?

When recording a Marine's weight, it is essential that both feet are flat on the scale. This position ensures a stable and accurate measurement. When both feet are securely positioned on the scale, it can provide a consistent reading of the person's weight without any discrepancies that may arise from shifting or uneven weight distribution.

Positioning both feet flat on the scale also helps to reduce errors that could be caused by balance issues or partial weight measurements, which could occur if only one foot is on the scale or if the feet are elevated. Maintaining proper posture and foot placement is crucial for achieving an accurate assessment of body weight, which is a vital component in monitoring body composition and overall health.