Occurred

Occurred past participle, past tense of oc•cur (Verb) 1. Happen; take place: “the accident occurred at about 3:30 p.m.”. 2. Exist in a place or under a particular set of conditions: “radon occurs in rocks such as granite”. Tibetan Adaptation to High Altitude Occurred in Less Than 3,000 Years Tibetans have mutations in numerous genes related to how the body uses oxygen. A comparison of the genomes of 50 Tibetans and 40 Han Chinese shows that ethnic Tibetans split off from the Han less than 3,000 years ago and since then rapidly evolved a unique ability to thrive at high  [ Read More ]