An enormous cloud of gas and dust that contracts due to gravity and forms stars is called a nebula.
the answer is A. nebula
B. makes no sense. A galaxy is a large grouping of solar systems.
C. Constellation. is wrong. a constellation is a pattern of stars that are visible from the surface of the Earth.
D. meteoroid. is also wrong. Meteoroids are large, pieces of rock that are floating in space that have no life, and contain numerous minerals.