Answer:
This question has little context, but I understand what you are trying to say.
The reason why dark moths survived while light moths weren't able to survive is due to the dark moths having conditions that allowed them to camouflage better than the light moths. An environmental condition that would allow this would be the dark moths and the light moths living in the same dark environment.
Explanation:
Alleles
I had bio a while ago though so I could be wrong...
<span>Rather than being learned, glucose aversion is inherited as an autosomal incompletely dominant trait, which appears to he controlled by
a single major gene. This was discovered through a study done on cockroaches, some were fed regular bait while some were fed bait laced with glucose. Through time they began to avoid the glucose.</span>
The answer would be proper strength since others do not make sense in detailed.