What peculiar feature did darwin find in the tortoises on the galapagos islands?
a. they were domesticated.
b. they had adapted to their surroundings.
c. they had access to better food sources.
d. they were a better breed than regular tortoises.

B. They had adapted to their surroundings. 

Adaption observed by Darwin on the Galapagos Islands also lead to the idea of Natural Selection: that those better suited to survive in their environment will continue to live and reproduce, passing on the traits to help the descendants survive as well.