What are the very cold (about 20 K), dense clouds of gas thought to be the most massive objects in the Galaxy called?

a) absorption clouds

b) molecular clouds

c) emission nebulae

d) dust clouds

e) reflection nebulae

The very cold (about 20 K), dense clouds of gas thought to be the most massive objects in the Galaxy are called molecular clouds.

Answer: Option B

Explanation:

Molecular clouds are basically the interstellar clouds made of dust and gaseous clumps. The clouds have an average density of 100 to 300 mcc with a temperature range of 10 to 20 K. The formation of stars takes place in the inner region of clouds. The size of molecular clouds may range from a few Light years to 600 Light years. A dar Nebula is the densest version of the molecular clouds.