Which hummingbird adaptation is most advantageous for supporting their high metabolism?

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."

i think the answer would be d

for example, no new evidence will demonstrate that the earth does not orbit around the sun (heliocentric theory), or that living things are not made of cells (cell theory), that matter is not composed of atoms, or that the surface of the earth is not divided into solid plates that have moved over geological timescales .

on island x the species needed to adapt because they were being subject to predators which didn't inhabit island y.