Final answer:
Barley base pairs were first developed in the region of the Fertile Crescent, which is present-day Iraq, where early forms of farming began around 6,000 to 5,000 years ago.
Step-by-step explanation:
Researchers think that barley base pairs were first developed in what is now the modern-day country of Iraq, an area that was part of the ancient Fertile Crescent. This region was one of the 'cradles of civilization' where some of the earliest forms of farming and domestication of grains such as wheat and barley enabled larger populations to settle and develop into complex societies. The domestication of these cereal grains in the Fertile Crescent paved the way for advanced civilizations to emerge in Mesopotamia and surrounding areas between 6,000 and 5,000 years ago.