New to dirt bikes and so many questions

[Higgalo]

Hi, I'm completely new to dirt bikes, and to message boards. I bought my son a used Tao Tao DB10. It runs pretty good but I found a few things I was not sure of. First I found a tube attached to the exhaust that runs to up under the seat attached to nothing, not sure what it is and if it's ok. Then I found a tube running from the carb/choke that ran to nowhere. There was a little port on the carb that looks like it could attach to but not sure. I'm attaching pictures of those two things. Lastly, what are some good places to buy replacement parts for Tao Tao's. Thanks for the help.