Let's fix the sentence step by step:
Original sentence: An iguana’s scales change colour when it gets warm or cool, dark or bright around them.
Issues:
1. "gets warm or cool" is unclear—does it mean the iguana feels warm/cool or the environment?
2. "dark or bright around them" is a bit confusing and incomplete.
3. "colour" is spelled correctly (British English), so it's fine if that is what you want.
4. The sentence should clearly say what affects the iguana’s scales.
Corrected sentence:
An iguana’s scales change colour when the temperature around it changes or when the light becomes dark or bright.
This says the scales change colour depending on temperature and light.
For a simpler sentence:
An iguana’s scales change colour when it gets warm or cold and when the light is dark or bright.
Would you like me to explain the meaning of this sentence too?