Final answer:
D. Peripheral vision is what you can see to the sides without moving your head or eyes, and it is essential for detecting movement and navigating your environment.
Step-by-step explanation:
What you can see to the sides is known as peripheral vision. This type of vision allows you to see objects and movement outside the direct line of sight—towards the edges of your visual field—without needing to move your eyes or head. Vision tests, such as the ones performed in an optometry office, often include examination of your peripheral vision. Visual acuity, as measured by the Snellen chart, for instance, determines the sharpness of your central vision, which is necessary to see details clearly. However, peripheral vision is crucial for overall visual experience and safety, allowing you to detect movement and navigate the world around you.