Dr. Proctor is conducting an experiment to see if hummingbirds will visit red flowers more or less often than they visit yellow ones. What will be the independent variable in?

The independent variable in Dr. Proctor's experiment is the color of the flowers, specifically red and yellow. This variable is manipulated to observe its effect on the frequency of hummingbird visits. The dependent variable would be the number of visits made by the hummingbirds to each color of flower.