The correct answer for the question that is being presented above is this one: "oxygen became available from cyanobacteria." About 1.2 billion years ago, eukaryotic and multicelled organisms evolved because oxygen became available from cyanobacteria.
        
             
        
        
        
Answer:
Eurocentrism is generally defined as a cultural phenomenon that views the histories and cultures of non-Western societies from a European or Western perspective. ... Rather, Eurocentrism is a systematic distortion of existing realities, with which most Western social theories and ideologies seem to have been contaminated
 
        
             
        
        
        
Answer:
Physical weathering enhances the rate of chemical weathering .
Explanation:
Physical weathering is the breaking down of rocks by various processes like freezing and thawing without altering the rocks chemical composition.
While, chemical weathering involves the disintegration and dissolution of rocks by the chemical processes like oxidation , carbonation and solution processes etc.
Generally a fractured rock can easily be weathered by chemical agents rather than a normal fractured rock.
So ,
when a rock is already subjected to physical weathering, the rock will develop cracks on it and when the chemical agents comes in contact with that rock, the chemical solution will penetrate into those cracks and will dissolve the rocks at a rapid rate.
 
        
             
        
        
        
Answer:
Mariana Trench is the deepest point on Earth
 
        
                    
             
        
        
        
Answer:  "the Earth's mantle" .
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The asthenosphere "floats" on the "mantle" [of the interior] Earth.
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