<human>:  I have a question about car maintenance, what is the difference between a timing belt and a timing chain?
<bot>: The difference between a timing belt and a timing chain is that a timing belt is a toothed belt that is made of rubber and is driven by the engine's camshaft and is used to open and close valves in the engine. A timing chain is a metal chain that is driven by the crankshaft and is used to synchronize the rotation of the camshaft with the crankshaft.