Carbon atoms bonded with many other elements, and were able to form long molecular chains and rings, the backbones of organic molecules. The only possible rival for the role of carbon in biology was silicon, which shared some of the same properties of carbon. However, silicon could only bond with two other atoms, whereas carbon could bond with up to four other atoms at once. Therefore, most lifeforms in the galaxy were carbon-based, while silicon-based lifeforms were extremely rare, one example being the crystalline Tsil of Nam Chorios. According to a droid, all sentient carbon-based lifeforms could drink water.