What should not be done with your legs during impact with branches?

Keeping your legs uncrossed during an impact with branches is crucial for maintaining control and minimizing injury risk. When legs are crossed, it can create a greater likelihood of entanglement, increasing the chance of a more severe impact or injury due to the lack of freedom of movement. By ensuring that your legs are apart and unimpeded, you can better manage your positioning and response to an unexpected obstruction during descent.

The other choices relate to positioning that can either offer hindrance or a more dangerous scenario in an emergency impact situation. Keeping feet together might seem stable, but it can lead to balance issues and decreased ability to maneuver. Stretching legs out could lead to catching on branches and result in a more dangerous fall. Pulling legs up towards the chest might help reduce the risk of hitting objects below, but would also similarly limit your ability to adjust your body position, possibly resulting in inadequate preparation for impact.