The sentence you wrote is mostly clear, but it can be improved for grammar and clarity. Here is the original sentence:
“An iguana’s scales change colour when the room gets warm or cool, and dark or bright.”
Here are some suggestions:
- Use consistent terms: 'colour' is British spelling; if you prefer American English, use 'color'.
- Clarify the conditions: It's better to say the room becomes warm or cool (for temperature), and bright or dark (for light).
- Improve the sentence flow: The phrase 'and dark or bright' sounds a bit awkward after 'warm or cool'.
A corrected version can be:
“An iguana’s scales change color when the room gets warm or cool, and when it becomes bright or dark.”
This way, it is clearer that the scales change depending on temperature and light.
Or, if you want it shorter:
“An iguana’s scales change color when the room becomes warm or cool, and bright or dark.”
Both sentences are grammatically correct and easy to understand.