Question

use the text to compare and contrast nebulae and galaxies.
nebulae and galaxies are two types of celestial objects. most are so far away that they can be seen only with a telescope, but astronomers can gather enough information to tell them apart. a nebula is a cloud of interstellar dust particles and ionized gases, while a galaxy is a large collection of stars held together by gravity. one of the main differences between the two is their size. a galaxy is generally much larger than a nebula. in fact, a galaxy can contain a nebula, but a nebula cant contain a galaxy. when a large amount of mass builds inside a nebula, the gravitational attraction increases, and the nebula collapses to form a star. however, while galaxies contain stars, a galaxy as a whole will not collapse to form a star. in addition, galaxies are found in clusters or groups in space, but nebulae havent yet been observed in these patterns.

Explanation:

• Are celestial objects: The text states "Nebulae and galaxies are two types of celestial objects", so both should be checked.
• Are collections of stars: A nebula is "a cloud of interstellar dust particles and ionized gases", while a galaxy is "a large collection of stars held together by gravity", so only galaxies should be checked.
• Collapse to form stars: "When a large amount of mass builds inside a nebula...the nebula collapses to form a star. However...a galaxy as a whole will not collapse to form a star", so only nebulae should be checked.
• Have been found in clusters: "galaxies are found in clusters or groups in space, but nebulae haven't yet been observed in these patterns", so only galaxies should be checked.

Answer:

• Are celestial objects: Nebulae (✔), Galaxies (✔)
• Are collections of stars: Nebulae (✖), Galaxies (✔)
• Collapse to form stars: Nebulae (✔), Galaxies (✖)
• Have been found in clusters: Nebulae (✖), Galaxies (✔)