Why are trees considered to be producers?
a. they do not need food to survive in an ecosystem
b. they depend on consumers to them make their food
c. they get their food from other sources
d. they make their own food using energy from the sun

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