not unless they write on your wall no
Even though it is a common misconception, you cannot tell who is looking at your profile on Facebook, nor can anyone see whose profiles you have been looking at.
There is no way to tell who is looking at your profile in Facebook. There are many applications that claim to tell you who views your profile, but none are recognized as useful by Facebook.
nope
No you can't.
it means to tell them about it
by looking on your profie and look on friend requests at your home page and it will say the number of requests you've got
I guess that you will be able to tell by how they speak to you!
You can't tell if someone is gay by looking at their hands.
No but they will know that your on a mobile
Yes. You can't do anything with them. Nothing.
No Facebook will not tell your parents about your account, but they are able to search for it even if they don't have a facebook unless you change your privacy settings. Be careful though because if you are friends with someone who may know your parents they may tell them and then you will get caught.
You can tell by looking at the space you use. It is written at the bottom of the page. The bottom says the total space and the percentage you have used.