What are Nebulae and what are they made of?

See explanation.

Explanation:

Nebulae are interstellar cloud of dust, hydrogen, helium and other ionized gases.

Nebulae are the places where stars are born. Nebulae formed when portions of the interstellar medium undergo gravitational collapse.

Nebulae are made of dust and gases; mostly hydrogen (about seventy-five percent) and helium (about twenty-five percent).

The interstellar gases are very dispersed and the amount of matter adds up over the vast distances between the stars.

Nebulae are made of dust and gases-mostly hydrogen and helium. The dust and gases in a nebula are very spread out, but gravity can slowly begin to pull together clumps of dust and gas.