Resistance '

Resistance is the opposite to a current flowing through a component. Every component in a circuit has a resistance, including the wires.

Average drop is a loss of energy that occurs when electrons move through a component. As electrons travel through a component with a high resistance they lose more energy and there is a greater voltage drop. When electrons flow through a component with a low resistance they lose less energy than when they flow through a component with a high resistance

Wires also have resistance. If a wire is longer it has a higher resistance. This is because the electrons have to travel further, so they will lose more energy. A wire has a lower resistance when it's wider because more elections can fit into the same bit of wire.