They are rich in hydrogen and helium, they have unlimited supply of hydrogen, they have a strong gravitational pull.
Explanation:
Space where huge size of gaseous and dust cloud is present is called nebula. It is mainly made of hydrogen and helium. Nebula exist in the space which is between the stars and it is call as interstellar space.
Helix nebula is closest nebula which is near the earth. It’s distance from earth is about 700 light years.
Dark nebulae are very dense as well as cold. Nebula can be divided into dark nebula and bright nebula. The gas which is present between the stars is always combine with solid grains cosmic dust.
689 decilitres =
68900 millilitres
