There is a mistake in each sentence ?? 1- Asteroids may be fragments of a planet shattered long ago or from material the nuclei of old comets 2- the first native Americans to occupy what is now the southwestern united states were the big-game hunters ,which appeared about 10000 b.c 3- some hangers ,buildings used to hold large aircraft ,are very tall rain occasionally falls from clouds that for along the ceilings 4- most sand dunes are always in motion as wind pushes sand upward one side of each dune ,over the top ,and down the other side