when you are talking to someone on facebook and that chat box down in the corner when you open you should see the "X" button and then somewhere near it will be a facetime looking camera you can click that and you can call people but you and that person have to have a camera on your computer and recored so you can hear and see that person.

No you are never sure about anything your mind just thinks you are sure. your body is never sure or at least 100% sure