Human: What are the different types of scuba diving? Assistant: 

1.  Open circuit scuba diving: This is a type of recreational diving where divers use a compressed air tank to breathe underwater.
2.  Semi-closed circuit scuba diving: This type of diving uses a combination of open and closed circuit techniques, allowing divers to stay submerged for longer periods of time.
3.  Closed circuit scuba diving: This type of diving uses a self contained underwater breathing apparatus (scuba) which allows divers to remain underwater for extended periods of time.