Ineed with 6. i don’t know how to approach this problem.

-- The total resistance of the circuit is (2 ohms in the resistor) plus
(1 ohm in the light bulb) = 3 ohms.

-- The current in the circuit is (3v)/(3 ohms) = 1 Amp

-- The voltage across the 2-ohm resistor is (1 Amp) x (2 ohms) = 2 volts
(points 1 and 2)

-- The voltage across the 1-ohm light bulb is (1 Amp) x (1 ohm) = 1 volt
(points 2 and 3) 

-- The voltage between points 3 and 4 is (1 Amp) x (zero ohms) = zero

-- If the bulb was replaced with wire, the total resistance in the circuit
would be only the 2-ohm resistor.

-- The current would be (3v)/(2 ohms) = 1.5 Amp.

-- The resistor would be connected directly across the battery.
So the entire 3 volts would appear across the resistor.
Points 2 to 3 and points 3 to 4 would be only wire, with no voltage drop.