If the open ports are the ones being used by the server (e.g. Apache) or any other running service, you obviously can't close them.
All other ports are closed by default.
If you want to close the ports as a security measure, you should know there's (almost) nothing a hacker can do to a open port, if the application using it is legit and it doesn't have any security holes.
If you want to force a port to be closed and stealth all closed ports, you can use a firewall.
Port 21 is for FTP traffic and port 80 is for HTTP traffic, I dont do any web developing but I think some of those other ones are normal web ports as well, you close em and the site or whatever it is wont work.