No they cannot. It is against the code.
You can't enjoy Facebook, Facebook is a noun. People enjoy USING Facebook :)
You cannot access Facebook account using Gmail. You have to use it using the Facebook site only. Gmail is just for confirming the account.
yes you can login using mobile number in facebook on the main facebook login page.
Facebook started using hashtags in 2013. Many people like to use hashtags on Facebook and Twitter.
Log in using Facebook.
Yes, you could before, using Habbo Hotel's Facebook App, but since Facebook's Updates on Dec. 9th, you can no longer buy Habbo Credits, using Facebook Credits.
No, you can't delete Facebook using Gmail. To delete Facebook, you have to go on their website. Gmail just is an interface.
It costs nothing to open a facebook account.
No, You cannot log on to Facebook from WikiAnswers. You can sign into WikiAnswers using your Facebook account however.
You cannot change your cover photo on Facebook using a Kindle Fire. You will have to change your cover photo on Facebook using your PC computer or your laptop or netbook.
Yes, but only using the Facebook Messenger app, which supports about 20 emoticons you can't get using regular facebook. They still show up properly in regular facebook chat though