Darwin visited the galápagos islands while on a journey aboard the beagle. which observation led darwin to start thinking about evolution

"The animals on the Galápagos Islands were recognizable as similar to their counterparts in other regions of the world, but had a range of noticeable differences from those counterparts. Many animals had small variations from island to island."

this is the answer i believe

Observing the finches

answer; 60-100; beats per minute