A Biologist Studies a Population of Birds for 25 Years

A biologist studies a population of birds for 25 years. Each year the biologist records the amount of rainfall and the density of birds (number of birds per 100 square meters). In addition, the biologist determines the survival rate for eggs laid that year. The biologist then plots egg survival rate against both rainfall (graph a) and density (graph b). In each plot the individual points represent the data for one year of the study. Based on these data, does this population of birds appear to be subject to positive density-dependent population regulation, negative density-dependent population regulation, or density-independent population regulation? As part of your answer, list the prediction for each type of population regulation and explain whether the data meet that prediction.