Determine whether each circuit element is a source or a resistor

[sporus]

Homework Statement

In the circuit as shown in Figure 4, there are three independent sources and
five ordinary resistors.
(a) Determine which of the circuit elements are sources and which are
resistors?
(b) Determine the value of the resistance for each of the resistors.

http://img845.imageshack.us/img845/5295/unledvhg.png

Homework Equations

The Attempt at a Solution

Since every element can be reduced to an equivalent resistance, voltage, and branch current, it is impossible to tell whether any given element is a source or a resistor.

My answer is wrong, and I couldn't find any similar questions or examples in my textbook to reference. The professor did not address this in class and I do not know where to start.

EDIT: I only need help with part a. I did part b with no problem of course.

 

[gneill]

HINT: Only sources can increase potential in the direction of current flow. Resistors always show a potential drop in the direction of current flow.

 

[sporus]

Ah, thanks. That makes a lot of sense. So h, c and e are sources, and the rest are resistors?

 

[gneill]

Yes. Check your results by solving for the currents in your finished circuit.

 

[sporus]

Thanks again. Wish there was a kudos button :)

 

[gneill]

You're quite welcome!