Tortoises found on the Galapagos Islands can have varied phenotypes. One of the variations in the phenotypes is with regard to their shells. They can have a domed shell with a hood above the head. The shells without domes lack the hood above the head,
such that the tortoise's neck is always pointing downward. A group of evolutionary biologists studied the tortoise population for
generations on these islands. The study coincided with a severe drought in the area that lasted many years. The data for the
changes in tortoise shell shape is shown here. Evaluate the data and select the statement that is best supported by this data.