Gases take up a lot of space because
a. they have weak chemical bonds.
b. their molecules have very little attraction for one another.
c. they contain very few atoms.
d. they have a small molar mass.

Gases take up a lot of space because their molecules have very little attraction for one another. The correct option among all the options given in the question is option "b". Under normal circumstances, gases fill up the entire space of the container in which it is kept. This is only possible because there is minimum amount of attraction between the molecules.

Answer b is the answet