Question

How does galaxy composition typically relate to the age of the stars in the galaxy?(1 point)
Responses

Star aging emits gas and dust, so galaxies with the youngest stars typically have the lowest proportions of dust and gas.
Star aging emits gas and dust, so galaxies with the youngest stars typically have the lowest proportions of dust and gas.

Stars form from dust and gas, so galaxies with younger stars typically consist of higher proportions of dust and gas than other galaxies.
Stars form from dust and gas, so galaxies with younger stars typically consist of higher proportions of dust and gas than other galaxies.

Star formation and the presence of young stars is common across galaxies, regardless of the proportions of dust and gas present.
Star formation and the presence of young stars is common across galaxies, regardless of the proportions of dust and gas present.

Star formation consumes dust and gas, so galaxies where stars are oldest typically consist of higher proportions of dust and gas than other galaxies.
Star formation consumes dust and gas, so galaxies where stars are oldest typically consist of higher proportions of dust and gas than other galaxies.

Answer 1

Stars form from dust and gas, so galaxies with younger stars typically consist of higher proportions of dust and gas than other galaxies.

Explanation: Gas- and dust-rich galaxies (e.g., spiral, irregular) have ongoing star formation and many young, blue stars; gas-poor ellipticals mostly contain older, red stars.