Well for a start, this makes absolutely no sense, "discovered a fuel that burns so hot that it becomes cold."
<span>And yes, it's not science if the experiment can't be repeated. In fact they should WANT it to be repeated so that you can get credit for discovering something new and then possibly harness this effect to produce useful applications. </span>
<span>For all we know they had a fewer of LN2 in the lab that got shredded by the blast, LN2 could certainly have frozen many things (not metal though, since metal is already solid at room temperature, (except for mercury)), and afterwards would leave no trace.</span>
This statement would be best characterized by the law of conservation of momentum—choice C.
