After a century of speculation, scientists confirmed in 2006 that bones buried in a spanish church belong to christopher columbus. dna samples taken from bone fragments confirm that at least some of the explorer’s remains were buried in spain. scientists compared the bones to remains known to be from diego columbus, christopher’s brother. it was a perfect match. what is the main idea of the paragraph? scientists studied dna samples from christopher columbus. christopher columbus had a brother. christopher columbus was an explorer. christopher columbus was buried in spain.

(1) fire extended humans’ geographical boundaries by allowing them to travel into regions that were previously too cold to explore. (2) it also kept predators away, allowing early humans to sleep securely. (3) fire, in fact, has been a significant factor in human development and progress in many ways. (4) other obvious benefits of fire are its uses in cooking and in hunting. (5) probably even more important, however, is that learning to control fire allowed people to change the very rhythm of their lives. (6) before fire, the human daily cycle coincided with the rising and setting of the sun. (7) with fire, though, humans gained time to think and talk about the day’s events and to prepare strategies for coping with tomorrow. the sentence that expresses the main idea is: (type the number of the sentence. then click “go.”)