An animal with no cone cells would have difficulty with which visual ability?

• A. Color vision
• B. Depth perception
• C. Motion detection
• D. Light sensitivity

Answer: (A)

Color vision comes from cone cells in the retina. Cone cells are specialized for detecting different wavelengths of light, and together they allow the brain to distinguish colors. Without cones, an animal would rely on rod cells, which are much more sensitive in low light but respond primarily to brightness and do not distinguish colors. So color vision would be greatly impaired or entirely absent.

Depth perception, motion detection, and light sensitivity each rely on different aspects of vision. Depth perception mainly comes from binocular cues and perspective, which don’t require color information. Motion detection can still occur with rod-driven vision since it’s about noticing changes over time, not color. Light sensitivity is primarily a function of rods, especially in dim light, so that ability would remain even without cones.