A sprocket
A sprocket is a toothed wheel whose teeth engage the links of a chain.
It's the small toothed wheel that the chain runs over by the rear wheel, although in engineering terms it is any toothed wheel designed for a chain, including the one rotated by the pedal and crank on a bicycle.
They have teeth because they are toothed whales.
They are toothed whales.
Dentatus, "having teeth".
Saber toothed cats did not have black teeth. Many saber toothed cat fossils come from the La Brea Tar Pits, where the teeth and bones were preserved. The asphalt that preserved the bones, though, also stained them.
A red maple leaf is toothed, which means it has serrated edges resembling teeth.
Is the Pope Catholic! (Yes they do.)
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they have baleen.
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In the drive train you have the front chainwheel/ring and the rear sprocket that both engage the chain. The pointy bits on sprocket and chainwheel which allows the chain to grip are called teeth. The ratio between the tooth counts is what determines which gear ratio the bike has.