The correct answer is - cyanobacteria.
The atmospheric oxygen came from the cyanobacteria. These were one of the earliest living organisms on Earth. The cyanobacteria was using photosynthesis in order to create its own food. The photosynthesis process requires sunlight, carbon dioxide, water, and oxygen. The oxygen is mostly released as a waste product from the process of photosynthesis, thus the cyanobacteria were literally releasing oxygen that was ending up into the atmosphere. As more and more cyanobacteria there were across the planet, more and more oxygen they were releasing into the atmosphere, slowly changing the composition of the atmosphere, and setting the basis of it as we know it now.
I did my research on this question. It would be... D
Climatologists warn of a tipping point when global temperatures trigger catastrophic events like the melting of the polar ice cap and this will result in sea levels rising more than 50 feet. The correct option among all the options that are given in the question is the last option. That would be the day of doom for most people living on planet earth.
Answer:
Core is made up of <em>a</em><em>l</em><em>l</em><em>o</em><em>y</em> which is the combination of <em>I</em><em>r</em><em>o</em><em>n</em><em> </em><em>,</em><em> </em><em>N</em><em>i</em><em>c</em><em>k</em><em>e</em><em>l</em><em> </em><em>,</em><em> </em><em>G</em><em>o</em><em>l</em><em>d</em><em> </em><em>,</em><em> </em><em>P</em><em>l</em><em>a</em><em>t</em><em>i</em><em>n</em><em>u</em><em>m</em><em> </em>and <em> </em><em>U</em><em>r</em><em>a</em><em>n</em><em>i</em><em>u</em><em>m</em><em>.</em>
(From Google)
