How did scientists obtain environmental DNA (DNA) from carp in the waterways near Chicago?

A. They collected water samples and isolated DNA the fish had left
behind.
B. They extracted DNA directly from the wastes of the fish.
C. They collected carp eggs, from which they extracted DNA.
D. They captured carp and extracted DNA directly from the fish.

The return of the wolf to yellowstone national park will probably affect the bird population to some degree, not significantly. while wolves will hunt birds when necessary, they prefer to hunt larger prey. the bird population will most likely only be affected when hunting is scarce for the wolves. birds of prey will also probably not be affected as much as other birds who spend more time on the ground hunting for food as the tend to spend more time in the air or in trees since they do not need to stay on the ground for long due to the nature of the way they hunt.