Can you explain simply why these four molecules are not isomers, but identical compounds?

Just rotate the first molecule around different axes and you can move it around to look like any of the other three. You don't need to break any bonds to make them look the same.

hey i left the rest of the question on chem under a comment that u asked where the rest of question was thank u!!1

you know im bad at science lol how should i know?