Controls 101

I was hoping someone could help me with the following multiple choice questions that I am not 100% sure about. The text books I have do not clearly state the differences.

Which of the following is reduced with an addition of negative feed back

1. Input signal
2. Feedback signal
3. System Gain
4. System Stability
5. System Reliability

Which of the following can be attributed to Proportional + Derivative Control?

1. It improved disturbance rejection
2. It makes the system more stable
3. It reduces the system steady state error
4. It reduces the magnitude of the disturbance signal

What is the difference between noise and disturbance?

1. There is no difference both are unwanted signals in the system
2. Disturbance is a random occurrence while noise has a distinct pattern
3. Disturbance is a discrete event while noise is a continuous event
4. Noise has a broad bandwidth spectrum while disturbance has a high pass characteristic.