It’s hz and bandwidth, 5ghz is better then a 2.5ghz but the wavelength is more condensed so it won’t travel so far so the 5ghz will be faster but the 2.5ghz will go further.
No you would click save or save as
Check who you are sending it to before you hit send
once you have sent the email it will only go to the server which then the person receiving it would log on therefore requesting the emails recived.
I'm not 100% sure my answer is classed as correct but I would say it doesn't go to a computer it just gets stored on a server in till requested
