A mathematician, a physicist, and an English teacher are reading your assignment and they come upon an instance of “QED”
The mathematician remarks that you must have meant “Quod Erat Demonstrandum” which is conventionally placed at the end of a mathematical proof.
The physicist remarks that you must be referring to “Quantum Electrodynamics” which is the theory of elementary particles in the context of special relativity.
The English teacher wonders WHY THE FUCK you are using an acronym when the meaning is not clear to a mathematician or a physicist.
Moral of the story: English teachers are mean and should never read anything you write.