Answer:
1.) stromatolites
2.) photosynthesis
3.) Ordovician
4.) Cambrian
5.) oxygen
6.) As Earth cooled, carbon dioxide dissolved in the early ocean. Cyanobacteria consumed carbon dioxide and converted it to oxygen. Methane was removed from the atmosphere as oxygen was produced, eventually leading to the Cambrian Explosion.
7.) Metabolic processes that use oxygen produce more energy than anaerobic metabolism. Simple diffusion of oxygen would limit the size of a multicellular eukaryote, but animals evolved ways to transport oxygen to their tissues, which permitted an increase in size.
Explanation:
From Penn
The answer to this is the last option i think
Answer:
well, I'm no college student but using common sense you need more than one so when one fails the other can come in and hopefully succeed.
Explanation:
High central plateaus sandwiched between tall mountains
Answer:
Coal
Explanation:
it's expells the most CO2 into the atmosphere
