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gmatrant
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First identified in 1969, komatiites are Earth's oldestknown volcanic rocks and contain three times as muchmagnesium as do most volcanic rocks. This chemicalcomposition suggests that komatiites formed from thehottest lava known ever to have erupted: a highconcentration of magnesium changes the physicalproperties of lava so that unusually high temperatureswould be required for the lava to exist as a liquid.
Komatiites' discovery was surprising in light of then-current geological theories about magmas, moltenrock that forms in the Earth's mantle (the layerbeneath the crust) and composes volcanic lavaeruptions. Prior to 1960, geologists Bowen and Hessdisagreed over whether or not the very hightemperatures needed to produce magmas rich inmagnesium could have existed on Earth. Hesssuggested that the presence of water, probablyreleased from minerals decomposing in the Earth'smantle, might have meant that a high-magnesiummagma could have existed at a lower temperature. ButBowen showed experimentally that the hightemperatures were indeed necessary. By 1960, it wasgenerally accepted that volcanic rocks with such highlevels of magnesium could not exist, and thus thediscovery of komatiites changed geologists' assumptions about the characteristics of the Earth'smantle around the time of the formation of komatiites,between 2.5 and 4 billion years ago.
Which of the following most accurately describes theorganization of the passage?
A. Two divergent views of a scientific phenomenon arereconciled.
B. A phenomenon is described and its scientificsignificance is discussed.
C. The discovery of a scientific phenomenon is tracedand its implications for further research are suggested.
D. A long-standing scientific theory is examined andrecently discovered evidence is shown to support it.
E. The ways in which a particular geologicalphenomenon is exceptional are detailed and classified
[spoiler]OA is B. Can you please tell me why D is not correct?[/spoiler]
Komatiites' discovery was surprising in light of then-current geological theories about magmas, moltenrock that forms in the Earth's mantle (the layerbeneath the crust) and composes volcanic lavaeruptions. Prior to 1960, geologists Bowen and Hessdisagreed over whether or not the very hightemperatures needed to produce magmas rich inmagnesium could have existed on Earth. Hesssuggested that the presence of water, probablyreleased from minerals decomposing in the Earth'smantle, might have meant that a high-magnesiummagma could have existed at a lower temperature. ButBowen showed experimentally that the hightemperatures were indeed necessary. By 1960, it wasgenerally accepted that volcanic rocks with such highlevels of magnesium could not exist, and thus thediscovery of komatiites changed geologists' assumptions about the characteristics of the Earth'smantle around the time of the formation of komatiites,between 2.5 and 4 billion years ago.
Which of the following most accurately describes theorganization of the passage?
A. Two divergent views of a scientific phenomenon arereconciled.
B. A phenomenon is described and its scientificsignificance is discussed.
C. The discovery of a scientific phenomenon is tracedand its implications for further research are suggested.
D. A long-standing scientific theory is examined andrecently discovered evidence is shown to support it.
E. The ways in which a particular geologicalphenomenon is exceptional are detailed and classified
[spoiler]OA is B. Can you please tell me why D is not correct?[/spoiler]
A kudos or thanks would do great if my answer has helped you 
