Which of the following is NOT true for comets?
Some comets are believed to have originated in a region near the edge of the orbit of the outer planets in our solar system called the "scattered disk" that overlaps a region called the Kuiper belt.
Some comets are believed to have originated in the outer-most region associated with our solar system, called the Oort cloud.
The tail of a comet gives the comet its propulsion, like rocket fuel out the back end of a rocket.
The tails of comets generally point away from the sun and are made of two major parts–a dusty part (that curves a bit) and an ionic part.
Comets often contain significant amounts of water.