What best describes rods and cones functions?

• A. Rods detect color and cones detect brightness.
• B. Rods detect light and motion in low light; cones detect color and fine detail in bright light.
• C. Rods detect color in bright light; cones detect motion.
• D. Rods handle stationary objects; cones handle moving objects.

Answer: (B)

The main idea here is how photoreceptors in the retina differ in function. Rods are extremely sensitive to light, which lets us see in dim conditions and helps detect movement, but they don’t provide detail or color. Cones require brighter light, give us color vision, and provide sharp, fine detail because they have less pooling of signals (lower convergence) and are concentrated in the fovea.

This description matches the statement that rods detect light and motion in low light, while cones detect color and fine detail in bright light. The other statements mix up what rods and cones do: rods aren’t color detectors, cones aren’t primarily for motion, and the idea that rods handle stationary objects or cones handle moving objects oversimplifies vision and isn’t how these receptors are distinguished.