Question

dale often saw woodpeckers perched in trees in his backyard, but he never saw them at his bird - feeders. dale usually filled his feeders with sunflower seeds. he wondered if he could attract woodpeckers by adding a different type of food to the feeders. to test this idea, dale gathered eight identical bird feeders. he filled four with sunflower seeds. he filled the remaining four feeders with crushed peanuts. dale then placed the bird feeders in his backyard. over the next five days, he counted the number of woodpeckers that visited each bird feeder each morning. which of the following was an independent variable in this experiment? hint: an independent variable is a variable whose effect you are investigating. a dependent variable is a variable that you measure. the type of food used in the bird feeders the number of woodpeckers that visited the bird feeder each morning

Explanation:

An independent variable is what is changed in an experiment to see its effect. Here, Dale changes the type of food in bird - feeders to see if it attracts woodpeckers. The number of woodpeckers is what he measures (dependent variable).

Answer:

the type of food used in the bird feeders