Incentive to Move (IMAGE) University of Freiburg Caption Archaea are unicellular lifeforms without a cell nucleus -- like the far better researched bacteria. Credit Source: Sonja-Verena Albers Usage Restrictions None License Licensed 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.