PRINCIPLES VS DOCTRINES

In an on-line Religion class, I am taking, students are asked to read an assigned block of scripture, identify 2 doctrines or principles that stand out to them and post a comment about each one on the class discussion board.

The class is kind of fun but a challenge too.

So what is a doctrine?
And what is a principle?
What is the difference?

I did a bit of research - both religious research (it is after all a religion class) and secular research. I read a lot of definitions, information and references. Papa, who is always up for such intriguing questions, really did some digging and gave me some wonderful insights and references.

Here is what we learned:
Doctrine from a religious standpoint is revealed truth - simple, right? From a secular point of view it is any dogma, opinion, principle or tenet presented for belief. Doctrine is 'that which is taught. It is learning and teaching - Hmmm ...

Principles are much less clear cut. They are the basics of the practice of doctrines. In both instances, from both religious and secular points of view, the definitions differ very little. Principles are the fundamental truths, qualities or attributes of any given topic: math, science, language, religion, philosophy, politics etc and etc. A principle is the beginning, origin, essence, source, fountainhead, guide, commencement, or initial state. It is the root or primary element, law or force. It is rudimentary and has natural law as a basis.

Based on this research is every true principle a doctrine?

Can you name any doctrines?
What principles, when practiced, prove those doctrines?

Let me give you a couple of hints.
Hebrews 5:12
Moroni 9:20
Titus 2
1 Timothy 2:5
Doctrine and Covenants 10:67; 68:25;101:77-78
1 Nephi 1: 8-9, 19,
2 Peter 1:5-9

And please share your insights, opinions, doctrines or principles.