Blue-eyed people have been living in Europe for at least 7,000 years, scientists have discovered. A man who lived on the Iberian Peninsula before Europeans became farmers probably had blue eyes but dark hair and skin,  according to scientists who have sequenced   his DNA. This surprising combination of eye, hair and skin color1ing may not have been unusual during his lifetime, but it is no longer seen among modern Europeans, reported by the journal Nature. The man, a Neolithic hunter-gatherer known to scientists as La BranaI, is of great interest to scientists because he offers a snapshot  of what was in Europeans' DNA before agriculture spread through the continent. Experts have theorized that certain genetic feature spread quickly among humans after they adopted the farming lifestyle. La BranaI shows that at least some of their predictions were correct. The man's skeleton, along with that of a male companion, was discovered in 2006 in a cave in what is now northeastern Spain. The site, known as La Brana-Arintero, sits about 5,000 feet above sea level, and the cave provided a cold, refrigerator-like environment that preserved his DNA. In the lab, scientists were able to remove enough DNA from a single tooth to reconstruct La BranaI's entire genome  .  They compared it to the DNA of other ancient Europeans (including Otzi, the 5, 300-year-old mummy found in an Alpine glacier) and determined that he was a closer match with hunter-gatherers than with farmers. When it came to genes that would influence La BranaI's appearance, the researchers found that their 7,OOO-year-old subject had versions of two skin pigment  genes that are either very rare or nonexistent among Europeans today. Then they looked at other places in the genome that influence pigmentation  and found a mix of ancient and modern gene variants . Taken together, La BranaI's DNA "is likely to have resulted in dark skin pigmentation and dark or brown hair," they wrote. However, his DNA indicates that his eyes were most likely blue, the scientists found.This suggests that gene variants for light-color1ed eyes and skin did not spread together, they wrote, adding that La BranaI's combination "of dark skin and non-brown eyes is unique and no longer present in contemporary European populations. " Today, a blue-eyed person would typically have fair skin. To get some idea of whether La BranaI's color1ing was unusual for his day, the researchers will try to sequence the DNA of his companion, who has been named La BranaII. La BranaI remains as it was due to_.
dry weather a cold condition proper protection a high cave
Question: Blue-eyed people have been living in Europe for at least 7,000 years, scientists have discovered. A man who lived on the Iberian Peninsula before Europeans became farmers probably had blue eyes but dark hair and skin,  according to scientists who have sequenced   his DNA. This surprising combination of eye, hair and skin color1ing may not have been unusual during his lifetime, but it is no longer seen among modern Europeans, reported by the journal Nature. The man, a Neolithic hunter-gatherer known to scientists as La BranaI, is of great interest to scientists because he offers a snapshot  of what was in Europeans' DNA before agriculture spread through the continent. Experts have theorized that certain genetic feature spread quickly among humans after they adopted the farming lifestyle. La BranaI shows that at least some of their predictions were correct. The man's skeleton, along with that of a male companion, was discovered in 2006 in a cave in what is now northeastern Spain. The site, known as La Brana-Arintero, sits about 5,000 feet above sea level, and the cave provided a cold, refrigerator-like environment that preserved his DNA. In the lab, scientists were able to remove enough DNA from a single tooth to reconstruct La BranaI's entire genome  .  They compared it to the DNA of other ancient Europeans (including Otzi, the 5, 300-year-old mummy found in an Alpine glacier) and determined that he was a closer match with hunter-gatherers than with farmers. When it came to genes that would influence La BranaI's appearance, the researchers found that their 7,OOO-year-old subject had versions of two skin pigment  genes that are either very rare or nonexistent among Europeans today. Then they looked at other places in the genome that influence pigmentation  and found a mix of ancient and modern gene variants . Taken together, La BranaI's DNA "is likely to have resulted in dark skin pigmentation and dark or brown hair," they wrote. However, his DNA indicates that his eyes were most likely blue, the scientists found.This suggests that gene variants for light-color1ed eyes and skin did not spread together, they wrote, adding that La BranaI's combination "of dark skin and non-brown eyes is unique and no longer present in contemporary European populations. " Today, a blue-eyed person would typically have fair skin. To get some idea of whether La BranaI's color1ing was unusual for his day, the researchers will try to sequence the DNA of his companion, who has been named La BranaII. La BranaI remains as it was due to_.
A. dry weather
B. a cold condition
C. proper protection
D. a high cave
Answer: