Answer: Carbon Dioxide, Nitrogen, Argon, and oxygen.
Explanation: Earth's atmosphere is 78% nitrogen, 21% oxygen, 0.9% argon, and 0.03% carbon dioxide with very small percentages of other elements.
#11.) Phacops. It lived in the late Devonian Period (~400 million years ago).
#12.) Carbon-14 is a good radioactive isotope for determing the age of artifacts from a burial site thought to be associated with the most recent early humans because it is present in all organic matter (which humans have, of course).
#13.) 3, Devonian.
#14.) From the Devonian Period through the Triassic Period.
#15.) Cenozoic.
Answer:
I'm pretty sure that its A.
Explanation:
This tobacco plant is an example of a genetically modified organism.