318-Petroleum products vary so much in physical appearance because………. .
A)impurities change the nature of the substance so much
B)there is a great' demand for them in different forms
C)their chemical composition is made up of countless elements -
***D)carbon and hydrogen atoms can join in thousands of different ways
E)trace elements have a remarkable effect on hydrocarbons
There is an advantage to launching satellites from the equator. The Earth spins faster there, giving rockets a boost in reaching orbit that allows them to carry heavier payloads. But there are few suitable launching sites on the equator that would not involve political problems. Therefore, an international consortium has converted an oil-drilling platform into a floating launch pad, rocket assembly plant, and mission control. They hope to develop the capacity to launch commercial telecommunications satellites.
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