Final answer:
When observing a skier going down, the first thing to do is ensure their safety and control by assessing their technique and form.
Step-by-step explanation:
When an observer sees a skier going down, the first thing they should do is ensure the skier is safe and in control. This can be done by checking if the skier is maintaining proper form and balance, and if they are following the appropriate techniques for skiing down the slope.
For example, the observer should look for signs that the skier is making smooth turns, using their edges effectively, and maintaining a stable body position.
By assessing the skier's technique and safety, the observer can intervene if necessary or provide assistance if the skier is in trouble.