After His Return to England, Darwin Most Pondered Which Question

Multiple Choice

After his return to England, Darwin most pondered which question? ​

A) What could explain the great numbers and variety of species?
B) Does the fossil evidence support uniformitarianism?
C) Are the extinct and living armadillos the same species?
D) Did Galápagos mockingbirds have a common mainland ancestor?
E) Will natural selection work in England?