Which term describes large groups of stars, dust, and gas?

Which term describes large groups of stars, dust, and gas?

• A. Sun
• B. Solar system
• C. Nebula
• D. Galaxies

Answer: (D)

The idea here is recognizing structures by their scale and content. A galaxy is a gravitationally bound system that contains vast numbers of stars, plus gas and dust, spanning enormous distances. That combination—many stars with a shared reservoir of gas and dust bound together—defines a galaxy. In contrast, a sun is just one star, a solar system is that star with its planets, and a nebula is a cloud of gas and dust, often a birthplace of stars, not a bound collection of many stars. So the term that best fits “large groups of stars, dust, and gas” is galaxies.

The idea here is recognizing structures by their scale and content. A galaxy is a gravitationally bound system that contains vast numbers of stars, plus gas and dust, spanning enormous distances. That combination—many stars with a shared reservoir of gas and dust bound together—defines a galaxy.

In contrast, a sun is just one star, a solar system is that star with its planets, and a nebula is a cloud of gas and dust, often a birthplace of stars, not a bound collection of many stars. So the term that best fits “large groups of stars, dust, and gas” is galaxies.