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.
A meteor is a space rock that hits the atmosphere of the Earth. It's also another word for a shooting star. There are a lot of bodies in space, such as suns, planets, and moons. Those are all rather large, but there are smaller bodies too, such as meteors. A meteor is a smaller body in space that collides with the Earth or another planet.