The events leading up to Gatsby's death occur as result of Gatsby's love for Daisy and Daisy's terrible carelessness. The circumstances that lead up to his death, are of course, more complex than that explanation.
Myrtle and Tom are having an affair. Wilson is aware his wife is having an affair and has reason to believe that Myrtle's affair is with a wealthy man. He finds an expensive dog leash in the drawer, which reinforces his impression. When Tom and Gatsby switch cars while on their outing, Gatsby, who is with Daisy, allows her to drive. It is Daisy who hits Myrtle, causing her death. Wilson, seeing the car, believes it is Gatsby's car and that Gatsby had been Myrtle's lover. He finds Gatsby and kills him.
What would have happened if Gatsby had not loved Daisy so much and lied to protect her? What would have happened if Daisy had not been such a careless person? Are Tom and Myrtle to blame for having an affair? Do you think Wilson is the only person who is really responsible for causing Gatsby's death? As the story begins, do you think the seeds of Gatsby's death are already sown? What do you think the author wants you to conclude from Gatsby's death?
Ok first of all the best way to answer this question would be to look it up under the enotes chapter summaries. Daisy and Gatsby ride in a yellow car and run over Myrtle. Daisy is the one who in fact killed her but Gatsbay never reveals this. The next day Tom reveals to Wilson that Gatsby is the one who killed his wife. This then causes Wilson to go to Gatsby's house while he is swimming and kill him ,and then Wilson kills himself.