Answer:
deductive
Step-by-step explanation:
When Darwin constructed his theory, he began with deductive logic.
Each of the Galapagos islands has its own species of tortoise
The tortoises on each island are specialized for the particular habitat of that island
These islands have not been present for the entire history of the earth
There is a mainland tortoise that is very similar to these species, but none of these species are actually found on the mainland
It is highly unlikely that at one point all of these species were on the mainland, and all of them got washed out to these islands, but only one or two species survived on each island, and all of them went extinct on the mainland
Therefore, these species must have evolved from a common ancestor that drifted from the mainland
thelogicofscience.com