If you want to control the appearance of only specific content within a block you can always put the content in a div and assign to it your own custom class that you can add to the theme's css. If for some reason you have to do it inline, instead of writing the styles inline you can import your custom css file into the block so that you make any changes in that file and not in the block. 
Itamar Tzadok
Posts made by Itamar Tzadok
You might be able to achieve that by setting the text fields' (which are input elements) style either by modifying the relevant classes in the css file or by adding a description question to the quiz page with the relevant css definition.
Is there a way to set the database so that only the person who entered the entry can edit or delete?
That should be the default behavior. Of course teachers and admins have permissions to edit/delete all entries.Is there a way to limit the deleting to only the teacher?
You can try hiding the delete button and displaying it only to the teacher. One way to do that is by displaying the delete buttions only when the page is in edit mode (which only teachers and admins can bring about). This can be done with javascript. And so in this approach the teacher changes to edit mode by clicking the 'Blocks editing on' button which makes the delete buttons appear and then the teacher can delete an entry.
If you are the admin of your system you may be able to achieve that in some other way. I don't know (see http://docs.moodle.org/en/Database_permissions). If not and you would like to pursue the above option a little further and you need more details let me know.
Not sure I fully understand the requirement but if you need at the end some sort of a straightforward pass/fail indication such that >=80% is pass and <80% is fail, you may be able to achieve that by using a quiz as Mary suggests above but also a formula in the gradebook to convert the quiz score from >=80% to 100% and <80% to 0. If you use a designated grade item for the pass/fail calculation it will allow you to record and display both the original score and the pass/fail evaluation.