Answer :
So first off tell your teacher that the United States does not have a Democracy, it is the Federal Republic and never was a True Democracy, and that the main difference between a Democracy and the Federal Republic is that Democracy is led solely by the people unanimously voting for laws directly but the Federal Republic ( in layman's terms ) people unanimously vote for the group who gets to vote for the big decisions. Ie Electoral college. However please note that I am no expert and this is highly oversimplified.
However, If they don't accept that as a proper answer then say that it limits some of the things that may need to happen if a large enough group decides that it is unnecessary provided they are in the correct position to push against these things. Ie a war that we are currently not involved in but could become a major problem for us, say a choice is being made whether or not to engage in war a majority group in a big office somewhere in D.C. would be able to come to a decision for or against that action even if it's a choice that ends up being wrong.
However, If they don't accept that as a proper answer then say that it limits some of the things that may need to happen if a large enough group decides that it is unnecessary provided they are in the correct position to push against these things. Ie a war that we are currently not involved in but could become a major problem for us, say a choice is being made whether or not to engage in war a majority group in a big office somewhere in D.C. would be able to come to a decision for or against that action even if it's a choice that ends up being wrong.