Scientists may have solved one of life's greatest mysteries - the age-old question of whether the chicken or the egg came first. This has baffled us for centuries. However, researchers in Switzerland believe the egg came first. The scientists studied a tiny marine organism that dates back a billion years. They found it can form cellular structures that are similar to animal embryos. Thus, a prehistoric chicken did not need to lay an egg.

The organism was first discovered in 2017. It has offered many insights into ancient life. A researcher said it "allows us to go back in time a billion years". The genetics behind egg fertilization and embryo development were present before animal life existed. This means nature made eggs before chickens arrived. A simpler answer to the chicken and egg problem is that chickens appeared 10,000 years ago, whereas eggs arrived millions of years ago.