Section 2
a. What resistance do you need to limit current to 20 mA?
V = IR --> V/I = R, so:
5 V / (20*10^-3 A) = 250 ohms
b. Is 220 ohms a maximum or minimum resistance?
220 is a minimum resistance (which, at 5 V, results in a current of 22.7 mA, slightly above the forward current power rating of the red LED, 20 mA). Any less resistence, and the current flowing through the LED would exceed that rating.
c. What is the resistance range of the potentiometer?
10 kOhms (as written on the side)
Section 3
a. Does it matter what order the components of your circuit are arranged between power and ground? Why or why not?
It doesn't matter what order the components are arranged in, given that this is a series circuit - all resistances are added (so the resistor can go anywhere), and any interruption in the circuit causes all current to cease (so the interrupt or button can go anywhere).
Section 4
a. What is the minimum resistance required for use with the battery?
V = IR --> V/I = R,
9 V / (20*10^-3 A) = 450 ohms, min resistence