Final answer:
A person who lacks cones in the retina will experience a visual defect known as color blindness or achromatopsia. Cones are responsible for detecting and perceiving color, so without them, the person will only be able to see in shades of black, white, and gray.
Step-by-step explanation:
A person who lacks cones in the retina will experience a visual defect known as color blindness or achromatopsia. Cones are responsible for detecting and perceiving color, so without them, the person will only be able to see in shades of black, white, and gray. This visual impairment affects the perception of color and can make it challenging to distinguish between different colors.