Fluctuating levels of the atmospheric gas, a potential tracer of alien life, have left researchers mystified By Robin George Andrews on November 20, 2019 Link> https://www.scientificamerican.com/article/nasas-curiosity-rover-finds-unexplained-oxygen-on-mars/?utm_source=newsletter&utm_medium=email&utm_campaign=daily-digest&utm_content=link&utm_term=2019-11-20_featured-this-week&spMailingID=61386192&spUserID=MTU4MDg3OTA0MzIwS0&spJobID=1763190583&spReportId=MTc2...