What was americas first space station gemini, skylab, mercury, or, apollo

skylab

Explanation:

Skylab was the first United States space station, launched by NASA, occupied for about 24 weeks between May 1973 and February 1974. It was operated by three separate three-man crews: SL-2, SL-3 and SL-4. Major operations included an orbital workshop, a solar observatory, Earth observation, and hundreds of experiments.

all matter is made up of atoms

in any element all atoms are the same

elements in a compound are always in a constant ratio: apex

cell/ tissue/ organ/ organ system/ body