If we cannot read it, we will not. Use a dictionary. Too many misspelled words circled in red by a reviewer are as good a tiebreaker as any other when there are two, three, four, or five equally good candidates vying for the same slot. Do not use a thesaurus. If the intent is to be yourself and present yourself accurately, awkward and unnatural word usage can work against you.
Institutions ask for the amount of information they can fairly compare between candidates.
More is not necessarily better. Maintain a strong academic pace for all four years of high school. Few things raise a red flag more than an academic profile that demonstrates a greatly reduced senior schedule. Answer the question. If a specific short answer exercise or essay question is asked, answer it.