How deeply does anybody go into this subject?

I just give a general overview of the various baroque, classical, romantic and contemporary areas - should I be going deeper and including tonality counterpoint etc, its seems to me that there is an awful lot to contend with, bearing in mind the amount of marks given for this section, and the time constraints available to get everything else done as well!

Any thoughts?

In my grade 5 aural, I was asked the period - which I confidently gave as "classical" - and then I was asked the reason(s) why. My teacher later said that the "period" pieces chosen are often an overlap between periods - which is why you need to provide further detailed knowledge of each period.