A landscaper accidentally had their leg crushed by a tree. Their femur was impacted with such force that a section of the bone completely shattered into fragments. What type of break is this

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