Tornadoes usually occur during which of the following seasons? * 10 points
spring and fall
fall and early winter
spring and early summer
summer and winter

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