The Evolution of Ax Levels

When we get into vertebrates, which means like they're a lot closer to human beings from an evolution standpoint, you'd be hard pressed to find something better than an and a salamander. The reason why we prefer to use ax levels is because they actually have a shorter generation time than many other salamanders. So it's still quite long compared to other research organisms in modern biology. We don't really know for sure why humans cannot naturally regenerate limbs but there are some similarities between the limb regeneration program and tumors.