Some species of roundworms are just one millimeter long. Their brains have only 302 neurons, compared to our own 86 billion, and lack any recognizable breathing system. They share only 35 percent of their DNA with human beings.
Some species of roundworms are just one millimeter long. Their brains have only 302 neurons, compared to our own 86 billion, and lack any recognizable breathing system. They share only 35 percent of their DNA with human beings.