The tube that connects the mouth to the stomach.
Sex is a reproduction system involving both male and female to partake in sexual activity intercourse to create an offspring between the two beings creating a living organism
Some advances is that organelles, cells, and the difference between the cells of a plant and a cell of an animal. This was an advance because not only did we discover new things but we learned how or body functions with them and how they work. Hopefully you got what you were looking for. :)
