The atoms of liquid mercury are a. close together, moving around one another. b. far apart, moving fast, and bouncing off the container walls. c. close together, vibrating in a rigid structure. d. not moving at all.

I believe your answer is A. close together, moving around one another, because any liquid's atoms are close together, but still able to move around.

Choice B was describing Gas atoms.
Choice C was describing a Solid.
And Choice D was not describing an atom, all atoms have to move or vibrate.
In conclusion, your answer is A.
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