Darwin’s voyage on the beagle and his subsequent work on evolution pushed human origins – and indeed the origins of life itself – into an unthinkably distant past. geologists had already demonstrated that the earth was far older than previously believed, undermining the calculation made by archbishop ussher (see chapter 2).

–a history of the world in 100 objects,
neil macgregor

based on context clues in the passage, what is the best definition of the word geologist?

a person who studies the earth
a kind of ship used for exploration
a type of religious leader
a period of change and uncertainty