Question

What is electrical resistance?

Answer 1

It's a feature that slows down the movement of charge along a path.

That was vague. But that's sort of it! In a circuit, there are many ways to cause resistance. It is a decrease in the net velocity of charge. See, electrons are always what's acting as "charge carriers". It's because they are free to move in metals, and even some other substances (like mineralized water). Protons, the other atomic particle with a net charge (+1), are pretty much stuck where they are - in the nucleus, making up the bulk of the atom's mass and whatnot....

Electrons "bang around" on the nucleus and other electrons and the walls of the wire a whole lot. But, as much as they tend to go everywhere, they will be biased to move towards a positive charge, like that of a battery. There is really a big concept of voltage here. Anyway, there are ways to make charge bang around more or be slowed for other complex reasons with different materials and orientations of wire and more.. One example is heat - that makes electrons more crazy, I think. But, anyway, this slowing down is always considered to be an effect of resistance.

There are actually different types of resistance, too. But I assume they're not too important at this stage in your learning, if you're learning fundamentals of physics electricity. Different current types affect how certain components resist. Special materials produce "diodes" which have a very high resistance if the current flows through it one way, and very low resistance if current flows through it the other way.