A "series" electrical circuit has exactly one (1) path for all the current
that flows in the circuit.
That tells us that ...
-- the current for every component in a series circuit has to flow through
all of the components;
-- if any one component is removed from a series circuit, the current stops,
and all of the components stop working;
-- the amount of current flowing past a point is the same at all points in a
series circuit.