In gymnosperms, pollination can occur by
bees
the wind
butterflies
pollen dropping from the top to the bottom of a tree

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