Colossal Biosciences is trying to bring back three extinct species. The process is called de-extinction. But some scientists are asking one big question: Why?

The ABCs of de-extinction

To revive a lost species, you need its DNA. Every cell in every living thing has a DNA molecule. This genetic code is like an instruction manual. It determines what the organism looks like, and how it grows and functions.

A complete set of an organism’s DNA is called a genome.