On the keyboard: why is A the only vowel in the middle line of letters when all the other vowels r on the top?

the qwerty keyboard came about because of the way early typewriters mechanisms worked. Each key was connected to a lever, which had the striker plate with the letter. the first typewriters actually had the keys in alphabetical order, but because of the frequency that certain letters are used in the english language, these alphabetical ordered typewriters frequently jammed. Someone redesigned the keyboard based on how often the letters are used, as opposed to alphabetically, and solved the jamming issue. Later typewriters had different, non-jamming mechanisms, but by that time everyone was used to the qwerty style keyboard. now, for computers, you can also get what is called a Dvorak layout keyboard, which is supposedly more intuitive to use, but because most people are used to the qwerty layout, there's not much push for change