In a DC circuit, it's the branch with the largest resistance.

In an AC circuit, it's the branch with the largest magnitude of impedance.

The resistance of the component on that branch of the circuit, if the resistance is higher less of a proportion of the total current of the circuit will travel through that branch, however, if the resistance is low a higher proportion of the current will travel through that branch of the circuit. The voltage through each branch stays the same.

The resistance of the component on that branch of the circuit, if the resistance is higher less of a proportion of the total current of the circuit will travel through that branch, however, if the resistance is low a higher proportion of the current will travel through that branch of the circuit. The voltage through each branch stays the same.

An ammeter reads the current that is flowing through a branch of a circuit. If there is a break within that same branch of the circuit, current will not be able to flow through that branch of the circuit as it forms an incomplete loop, so the ammeter will read 0 A of current.

If there is a break in a circuit in a branch that is not connected to the ammeter however, the ammeter will give a higher reading of the current. This is assuming that the break in the other branch does not short out the branch with the ammeter attached, and that the circuit can still form a complete loop without that branch.

A parallel circuit is an electrical circuit that has more than one current branch.