A _______ is a cloud of dust and gas inside a galaxy.
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. nebula.
A nebula is a cloud of dust and gas found within a galaxy, serving as a crucial component in the life cycle of stars. These vast regions can be sites of star formation, where gravitational forces cause the gas and dust to collapse, eventually leading to the birth of new stars. Nebulae can also be remnants of dead or dying stars, such as supernova remnants or planetary nebulae. They come in various forms, including emission, reflection, and dark nebulae, each playing a vital role in the universe's structure and evolution.