Frozen is an adjective. Past participle of frozen is freeze.
Usually, in a conclusion, you wrap up what you have been writing about the whole time. So, a conclusion is basically a summary of the whole text. You can introduce new ideas for the reader, but it is usually inadvisable. In a couple of sentences, you should finish your text, referring to the previous paragraphs and just wrap it all up nicely.
I believe the correct answer is: Using technical language
helps the author stress the complexity of the scientific advances and
technological achievements that Edison observed.
In this excerpt from “"Edison Marvels at the Magic of
Electricity" from the New York Tribune (October 19, 1922), author intentionally
incorporate such highly technical language to stress the complexity of the
scientific advances and technological achievements that Edison observed.
