Original sentence: Many  people believe that some crop circles which have particular features could not have been created by humans, and must be of paranormal origin.The people have come forward claiming to have created crop circles as a hoax, and others have demonstrated how complex crop circles are created,
Edited sentence: The creators of many crop circles have admitted they were a hoax, and many others have demonstrated how complex crop circles are created,  yet many believers in crop circles continue to insist that they are made by aliens and UFOs