What will happen if the cloud does not have enough mass?

The clouds were the fundamental unit in the formation of the solar nebula and were comprised of a significant amount of mass. These clouds have fused with the matter, interstellar dust particles along with gravity because of the force of gravity. Due to this fusion, the solar system started to form.

If the clouds were not of enough mass then they would simply scatter in space randomly. So in the absence of enough cloud mass, there would have not favorable conditions for the solar system to form.

the darker peppered moth species were favored due to the fact that the industrial revolution had made all the nearby trees a darker color instead of white.