The Chinese have built dams and reservoirs in order to A. create clean energy sources.
B. reduce dependence on foreign trade.
C. speed shipping times.
D. invest more in rural areas.

Why is the huronian supergroup rock formation particularly interesting to scientists? because it looks like a cross-section of a giant, stone encyclopedia because it formed during the period when oxygen began to accumulate in the atmosphere because it contains unusually large amounts of oxygen and sulfur because it dramatically altered the planet's development when it first formed