Finches living on the Galapagos Islands were critical for Darwin to develop his ideas. What key observation did he make about the finches?
A. The finches' feathers were structurally different to allow them to fly at different heights and speeds, depending on their local environment.
B. The finches' beaks were uniquely adapted as tools for them to eat the food that was available to them.
C. The finches' feathers were colored differently, providing camouflage within their unique environment.
D. The finches' beaks were colored differently, providing camouflage within their unique environment