What are the spiral arms of the milky way made of?

a. older stars and comets
b. variable stars
c. asteroids and comets
d. younger stars and gaseous nebulae

The spiral arms of the Milky Way are made of younger stars and gaseous nebulae. There are four spiral arms within the Milky Way galactic disc that start at the galaxy's center. The sun is five to 30 parsecs away from the center of the galactic disk.

The soviet union beat the us to the first successful launch, with the october 4, 1957, orbiting of sputnik 1, and later beat the us to have the first human in earth orbit, yuri gagarin, on april 12, 1961. the "race" peaked with the july 20, 1969, us landing of the first humans on the moon with apollo 11