<I>Pre pluribus unum</I> (IMAGE) Brown University Caption Stem cells have the potential for becoming different kinds of tissue, but certain characteristics -- stiffness, viscosity, size -- are telltale signs of what they're optimized to become. Credit Darling Lab/Brown University Usage Restrictions With credit as specified above. 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.