Answer :
When evolution was first proposed, observations of nature was used as evidence to support the idea.
Answer:
Option 1, observations of nature
Explanation:
History states that the first writing related to evolution could be found in the Greek sculpture. Two scholar Anaximander and Empedocles during Greek age proposed that organisms transformed from one form to another. This theory was based on the observations in the nature. The first evolutionary study based on fossil was conducted by Darwin and the first experiment based evolutionary study was conduction by Gregor Mendel in lab.
Hence the option 1 , is correct as the first study on evolution was based on natural observation.