Zebrafish, Danio rerio, fry on aquarium. Since the 1930s, zebra fish have been a model organism for studying human diseases.

- Image ID: R060PH
Zebrafish, Danio rerio, fry on aquarium. Since the 1930s, zebra fish have been a model organism for studying human diseases.
Paulo Oliveira / Alamy Stock Photo
Image ID: R060PH
The fertilized eggs, embryos, and fry are transparent, allowing scientists to easily observe and study topics such as tumor growth, brain tissue development, and blood vessel growth. Portugal