Which came first, the chicken or the egg?

This issue has always been controversial, but from a biological point of view, eggs existed first on the earth. About 450 million years ago, the earliest single-cell organisms appeared on the earth, and then gradually evolved into multi-cell organisms. The earliest eggs were produced by early invertebrates, who reproduced by hatching eggs.

Therefore, from the perspective of biological evolution, eggs should have existed earlier than chickens. However, in actual agricultural production, we usually have chickens first, and then hatch the next generation of chicks through the eggs produced by the chickens.

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