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
<span>It began with selective breeding in the ancient times where a population with desirable traits were bred with other population to achieve a desired set of traits. It then continued with the advance in the discovery of bacteria (Escherichia coli) and antibiotics. Then Watson and Crick discovered the structure of DNA. The latest advance being that of gene sequencing and gene editing tools. </span>
According to http://www.ucsusa.org/global_warming/science_and_impacts/science/ozone-hole-and-gw-faq.html#.WQjhDfW...
I think the answer is B.CFC
