Answer:
19th century
Step-by-step explanation:
Charles Darwin visited Galapagos Islands during his voyage on HMS Beagle in 1831. These islands are the chain of 22 islands located in Pacific Ocean on west coast of South America. Based on his observation during the voyage, he proposed the theory of natural selection in his book named as "On the Origin of Species by Natural Selection; or, The Preservation of Favored Races in the Struggle for Life" in 1859.