Question 23M.3.SL.TZ2.7
| Date | May 2023 | Marks available | [Maximum mark: 2] | Reference code | 23M.3.SL.TZ2.7 |
| Level | SL | Paper | 3 | Time zone | TZ2 |
| Command term | Distinguish | Question number | 7 | Adapted from | N/A |
Distinguish between the perception of colour in people with red-green colour-blindness and people with normal trichromatic vision.
[2]
- people with normal trichromatic vision can distinguish between red and green colours / are sensitive to red and green wavelengths;
- people with red-green colour blindness cannot distinguish between red and green colours / have low sensitivity to red and green wavelengths;
Accept an annotated diagram of the wavelengths showing the overlap of red and green.
Both answers may be given in one statement e.g., people with normal trichromatic vision can distinguish between red and green colours and those with red-green colour blindness cannot.
Many failed to make a distinction about the perception of colour. Quite a few answers focused more on the inheritance of colour blindness rather than the question that was asked. Many candidates mentioned the role of cones but some confused red-green colour blindness with the detection of shades of grey or the ability to see any colours. The question was straightforward, and candidates may have been looking for a more complex response than was required.
