Frog eggs (IMAGE) DOE/Argonne National Laboratory Caption Frog eggs like those pictured here release zinc when fertilized, much like mammalian eggs do. Credit (Image by Tero Laakso/licensed under CC BY-SA 2.0.) 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.