In humans, structures that show developmental homology with other chordates are

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

human-caused climate hope this

producers: apple trees, potatoes, carrots, grains, acorns, cabbage, grass, corn, lettuce

consumers: deer, mice, rabbits, chickens, squirrels, horses, worms, cows

predators: eagles, frogs, wolves, owls