people want gold ... so they sell BTC 
human parody ... here.
human parody ... here.Many of people still not have a faith on bitcoin yet
People who lost their faith.
People who were made to believe there is no future.But I still believing on bitcoin
It's not one person or persons. Think that there are many reasons and cirumstances. Mining is becomimg harder and more expensive
Well this is logical reason.
Plus bitcoin's security is still susceptible against hacker attack