The developing human yolk sac (IMAGE) Wellcome Trust Sanger Institute Caption The developing human yolk sac floats like a balloon in the exocoelomic cavity Credit Megumi Inoue, DOI: 10.1126/science.add7564 Usage Restrictions No restrictions. License Public Domain 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.