7. C Galaxy
8.A solar system
9.B universe
10. c earth
Answer:
It will take 1.85 hours to walk 12 km north.
Answer: By volume, dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1% at sea level, and 0.4% over the entire atmosphere.
Explanation:
The organisms that produced the oxygen gas in Earth's atmosphere in ancient times were <span>autotrophic eukaryotes. The correct option among all the options that are given in the question is the second option or option "B". I hope that this is the answer that has come to your desired help.</span>