Peter should develop his thesis statement during the prewriting stage. At this stage, an author thinks about what he is going to write about further down in the text, and a thesis statement is exactly that - a short summary of the main ideas that are going to be developed in a text.
The answer is due and dew. Homophones are words that sound the same but are spelled and used differently. Inthis case, doe and act are not the same pronounciation as do.