Question

1. choose the best answer.

the sun and most of the stars in the milky way are ______ stars that fuse hydrogen into helium.
○ main-sequence
○ red-giant
○ high-mass
○ intermediate-mass

Explanation:

To determine the correct answer, we analyze the stages of stellar evolution. Main - sequence stars are in the phase where they fuse hydrogen into helium in their cores. The Sun and most stars in the Milky Way are in this main - sequence phase. Red - giant stars have moved beyond hydrogen fusion in the core (they fuse hydrogen in a shell around an inert helium core). High - mass and intermediate - mass are descriptions of a star's mass, not the stage of hydrogen fusion (main - sequence stars can have different masses, but the key here is the stage of fusion). So the Sun and most Milky Way stars are main - sequence stars fusing hydrogen to helium.

Answer:

The option with "main - sequence" (the first option among the four, with the text "main - sequence").