A scientist discovers three populations of grasshoppers. The…

A scientist discovers three populations of grasshoppers. The number of each color of grasshopper (green, gray, and brown) has a strong correlation with the color of the soil in each population. To determine if the correlation is due to natural selection, the scientist places a few gray grasshoppers into the population of green grasshoppers, and a few gray grasshoppers into the population of brown grasshoppers. Then the scientist records which color of grasshopper is eaten most often by birds. Which of the four ecological science approaches is the scientist applying?