What following features is common to the systems of democracy found in the US and Canada?

As asked, the question is unanswerable, since the United States is NOT a democracy... it is a Constitutional Republic (recall both that Benjamin Franklin famously replied to a lady who asked him after the constitutional convention what form of government they had formed, "A Republic, Madam... if you can keep it!" and also the Words of the pledge of allegiance: "...and to the Republic, for which it stands."). The U.S. has democratic PROCESSES applied to the selection of SOME of its officials... that's it.

Canada, by contrast, IS a democracy. The Canadian Parliament can pass any law it pleases (provided that they can get the Queen to give that law her "royal ascension"... Canada is NOT, despite what you may have heard, a fully independent country... check the "King-Byng Affair" if you doubt me... both the British Crown and the British Parliament have rights in Canada: that's not independence). Great Britain has only ONE right in the United States: the right to send her trading vessels up the Mississippi river... see the relevant Treaties.

Citizens of the U.S. have been TOLD that they are living in a democracy since WWII... but calling a tail a leg does not make the name fit.

BY the way, I am a dual citizen of both these countries, have worked for both the U.S. and Canadian Federal Governments, AND run for, and held, elected office in both countries as well... so I DO know what I'm talking about.