The answer is D its tightly packed cells allow for proctection against harmful substances.
The first trophic level
they would want to eat the primary producers, which are located at the first trophic level. due to the 10% rule only 10% of the energy from the previous trophic level is passed on.
The evaluation of their DNA and short tandem repeats will let them know if the birds are related or not. The genetic linkage will provide information about their common ancestry as well as if they belong to the same species, or are closely related species.
I think it’s 12 but i’m not 100% sure.