What safety measure is taken to prevent injuries while sliding?

Keeping arms and legs inside the slide is essential for enhancing safety and preventing injuries during sliding activities. This measure minimizes the risk of limbs getting caught or struck by the slide's edges, which could lead to serious accidents. When riders maintain their arms and legs inside the slide, it also helps ensure that they maintain a streamlined position, reducing the likelihood of abrupt or uncontrolled movements that could result in falls or collisions with other riders.

The other choices introduce practices that could potentially compromise safety. Holding hands could lead to entanglement, standing up while sliding poses a significant risk of falling, and turning around can disrupt the rider's balance and orientation, increasing the chances of injury. Therefore, keeping arms and legs inside the slide stands out as the most effective safety measure.