Which of the following is NOT a function of cone photoreceptors?

• A. They provide high acuity color vision
• B. They function best in bright light
• C. They are densely packed in the fovea
• D. They are responsible for night vision

Answer: (D)

The main idea is how cones work compared to rods, especially with lighting. Cones deliver high-acuity color vision and are most active in bright light, and they’re densely packed in the fovea, which is why you can see fine detail and color in well-lit conditions. Night vision, however, is driven by rod photoreceptors. Rods are very sensitive in low light and enable vision in dim conditions, but they do not provide color vision and have poorer spatial detail. So the statement that is not a function of cone photoreceptors is night vision—cones are not responsible for that.