Ciona Embryo (IMAGE) University of Arizona Caption Ciona allows scientists to study in detail how cells interact to build complex organs. In this microscopic image, two of the cells that will form the heart were stained with a green fluorescent marker and can be seen in the lower portion of the tadpole-like Ciona embryo. Credit Katerina Ragkousi Usage Restrictions Usage only permitted with reference to this news release. Photo credit must be indicated. 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.