Answer:
When the lion turns its head to see zebras moving in the distance, its eyes would undergo a series of adjustments to focus on the new target. The adjustments involve the lens and the shape of the eye itself.
First, the ciliary muscles in the lion's eye would contract, which would cause the lens to become thicker and more rounded. This is known as accommodation and it allows the lion to adjust its focus from a nearby object to a distant object.
Second, the iris, which is the colored part of the eye, would adjust the size of the pupil. The pupil would dilate, or become larger, to allow more light to enter the eye. This would be important for seeing the zebras in the distance, which would be less bright than the nearby tourists.
Third, the retina, which is the layer of light-sensitive cells at the back of the eye, would adjust its sensitivity to light. The retina would reduce its sensitivity to bright light and increase its sensitivity to dim light. This would allow the lion to see the zebras in the distance more clearly.
Overall, these adjustments would allow the lion's eyes to focus on the zebras in the distance by changing the shape of the lens, adjusting the size of the pupil, and altering the sensitivity of the retina to light.