Question

During the revision phase for an argumentative essay, a writer should

Answer 1

Checks that the topic is clear and the language is effective>

Answer 2

Focus on things such as focus on style, tone, and word choice.

Taking an assessment of the style and tone of your essay, as well as word choices, are part of the revision process.  

Other things that might be in lists you're looking at would be part of the research process or drafting process or writing process.  Choosing your topic is a first step in the process, based on some preliminary research.  As you continue the research phase, you would be gathering facts and searching through reasons, evidence, claims and counterclaims, and opinions in regard to your chosen topic.   In the planning phase, you will establish a thesis and outline of your argument.  Then in the drafting  phase of your writing, you will put that clear argument into writing.  Once you have written your overall argument, then you would seek to write a strong conclusion to the essay (still in the writing phase).  

Matters such as proofreading, judging your word choices, checking the accuracy of your citations and bibliography list, and checking your voice, style and tone -- those are parts of the revision phase of your essay work.