Which of the Following Observations Helped Darwin Shape His Concept

Multiple Choice

Which of the following observations helped Darwin shape his concept of descent with modification?

A) Species diversity declines farther from the equator.
B) Fewer species live on islands than on the nearest continents.
C) Birds live on islands located farther from the mainland than the birds' maximum nonstop flight distance.
D) South American temperate plants are more similar to the tropical plants of South America than to the temperate plants of Europe.