Which is the most likely cause of the observed variation?
differences in the climate among the islands
competition among individuals for available food sources
competition among individuals for desirable mates
differences in egg size among the populations

How does the fossil record provide evidence that the modern whale evolved from the anthracotheres? a) the modern whale looks like their ancestor the anthracotheres. b) the modern whale has all of the same structures as their ancestor. c) there is not enough evidence to suggest the the modern whale evolved from the anthracotheres. d) the anthracotheres has a structure that is still present in the modern whale, but is no longer of use to the modern whale.