OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

What does it mean if someone is red-green colour blind?

1. They cannot see any colours

2. Their red or green cones in the retina are not working properly

3. It means they see in black and white

4. They see colours but confuse all shades

The correct answer is: Their red or green cones in the retina are not working properly

Being red-green color blind indicates that there is an issue with the function of the red or green cones in the retina, which are responsible for detecting those specific colors. In individuals with this condition, the cones may be absent, not functioning properly, or may perceive these colors inaccurately. This results in a reduced ability to distinguish between red and green hues, affecting their overall color perception. The other options do not accurately describe red-green color blindness. The condition does not mean that the person cannot see any colors at all, nor does it imply that they see only in black and white. Additionally, while individuals may indeed confuse red and green shades, it is more specific to certain colors rather than all shades. Thus, stating that the red or green cones in the retina aren't functioning properly captures the essence of red-green color blindness correctly.