Name two photoreceptors that mediate vision and their functional differences.

• A. Rods (low-light vision, high sensitivity) and cones (color vision, high acuity)
• B. Rods (color vision) and cones (night vision)
• C. Photoreceptors are located in the optic nerve
• D. Cones are responsible for motion detection

Answer: (A)

Two photoreceptors in the retina support different aspects of vision: rods and cones. Rods are extremely sensitive to light, so they serve nighttime or low-light vision and detect movement in dim environments, but they provide low spatial resolution and poor color discrimination. Cones require brighter light, give high visual acuity—especially in the center of the visual field where the fovea concentrates—and enable color vision through different cone types. That combination—rods for low-light sensitivity and cones for color and sharp detail—is why this pairing is the best description. The other statements misplace where photoreceptors are located (in the retina, not the optic nerve) or attribute functions incorrectly (cones for motion detection; rods for color and night vision).