Hello!
Coastal-plain swamp sparrows are gray brown whereas others are rusty brown.
There are a lot of genetic differences between the coastal-plain swamp sparrows and the others.
...
Genetic differences must be the reason of of the difference in color.
The gap is that we do not know whether the difference is caused by internal(i.e. genetics) or external (i.e. climate, food etc.) reasons.
Taking these into consideration
A) weakens the argument, because it clearly states that there is no genetic difference between coastal-plain swamp sparrows and freshwater swamp sparrows that affects plumage color, thus the reason of difference in plumage color should be external (for example food)
E) strengthens the argument, because it shows that under same external conditions(“identical diet and controlled conditions”) the birds grew plumage similar in color to that of their respective parents. This shows that external factors have no affect, thus the reason should be genetic.
Pls mark brainliest :)
