GED Science Practice

A galaxy is correctly defined as a collection of star systems. In astronomy, galaxies are vast systems that consist of stars, star clusters, planetary systems, gas, dust, and dark matter, all bound together by gravity. The Milky Way, for example, is a galaxy that contains our Solar System along with billions of other stars and their planetary systems.

The other options refer to different concepts: the first describes an ecosystem, which involves living organisms and their feeding relationships. The second option refers to a geographical feature, specifically a fjord or coastal inlet, which is unrelated to the astronomical context. The last option pertains to conditions affecting visibility in the atmosphere, which deals with meteorology rather than astrophysics. Thus, the definition that describes a galaxy as a collection of star systems is the most accurate in the context of astronomy.