A simple circuit has one battery and one recipient. Wires complete the path, letting electrons flow from one end of the battery through the recipient and on to the other end of the battery. You can use a switch in a simple circuit to control the flow of electricity. When the switch is open, the circuit is broken, and electricity does not flow. There are other types of circuits, too. In a series circuit, there is still only one path for the current to flow through. But there could be two or more recipients. Think about Christmas lights. If you remove one bulb from the string, all the bulbs go out. That's because the circuit is broken. In a parallel circuit, there are two or more paths for current to flow through. If you removed one bulb from a parallel circuit, the other bulbs would not necessarily go dark. The current would have another path to take. Based on the passage. how can you tell whether a string of lights is set up with a series circuit or with a parallel circuit?