Question

astronomers using a space - based telescope observe two galaxies in different stages of development. the first galaxy is a spiral type with clearly defined arms, active star formation, and abundant gas and dust. the second galaxy is elliptical with a smooth, rounded shape, little visible gas, and mostly older, red stars. scientists hypothesize that the elliptical galaxy may have formed from the collision and merger of two spiral galaxies billions of years ago. based on this information, which conclusion is most scientifically accurate?
○ spiral galaxies are older than elliptical galaxies because they contain more gas and dust
○ the elliptical galaxy likely formed from a merger that disrupted star formation and used up available gas
○ elliptical galaxies form when stars in spiral galaxies stop rotating
○ spiral galaxies eventually become elliptical as their arms collapse inward

Explanation:

Elliptical galaxies are hypothesized to form from the collision and merger of two spiral galaxies. This is a well - established concept in astronomy. Spiral galaxies have active star formation (due to abundant gas and dust), while elliptical galaxies have little visible gas and are mostly made of older stars. When two spiral galaxies merge, the disruption of their structure (like the spiral arms) and the consumption of gas (used up in star formation during the merger process) can lead to the formation of an elliptical - like structure.

Answer:

The elliptical galaxy likely formed from a merger that disrupted star formation and used up available gas.