Creatinine is a toxin produced during the metabolism of meat in our body. Therefore, people with lots of muscles or who eat lots of meat always have a relatively high creatinine level, but it usually fluctuates in the normal range: 0.5-1.3mg/dL.
comet definition An object that enters the inner solar system, typically in a very elongated orbit around the sun. Material is boiled off from the comet by the heat of the sun, so that a characteristic tail is formed.
The nucleus of a comet, which is its solid, persisting part, has been called an icy conglomerate, a dirty snowball, and other colorful but even less accurate descriptions. Certainly a comet nucleus contains silicates akin to some ordinary Earth rocks in composition, probably mostly in very small grains and pieces.