Illustration (IMAGE) Aarhus University Caption This illustration shows which elements have an effect on the reproductive succes of the musk oxen. Nitrogen, copper, selenium and molybdenum had a positive effect, whereas lead and arsenic had a negative one. Credit Science of The Total Environment Usage Restrictions May only be used in communicating this story. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.