Scientific investigations often lead to the formulation of new scientific questions. The observations Charles Darwin's work after he returned home from his voyage and studying the selective breeding of pigeons prompted him to ask which question?

A) Do living things change over time, and if so, how?
B) Are the Galapagos finches and those on the mainland the same species?
C) Are pigeons related to the Galapagos finches?
D) Can selection in nature also lead to a new species over time?