WHAT'S INSIDE: HUMAN BODY
- Body Parts
- Body Systems
During early pregnancy, both male and female human embryos develop something called milk lines, ridges that eventually recede into nipples. Why have some species lost this unisex trait, and can human men actually produce milk?
In the movie "WaterWorld," Kevin Costner's character has a mutation that gives him gills behind the ears. Could a mutation allow people to swim in the water just like fish --without having to use any sort of scuba equipment?