The great ocean conveyor belt occurs where?

a in the depths of the ocean, worldwide

b in the depths of the ocean at the equator

c on the surface of the ocean, worldwide

d on the surface of the ocean at the poles

Ascientist is designing an investigation to study the impact of invasive bird populations on local, native bird populations at backyard bird feeders. what population is most likely to be a control group for the investigation? amount of food number of bird feeders invasive bird populations local backyard birdfeeders without food