The increase in atmospheric oxygen during the Proterozoic was caused by ____
a. a decrease in worldwide volcanism.
b. a decrease in the size of oceans.
c. photosynthesis by cyanobacteria.
d. the appearance of land plants.
e. formation of banded iron formations
c
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Which chemical class includes ethanol (a type of alcohol)?
A. teratogens B. mutagens C. carcinogens D. neurotoxins
State-directed capitalism is a system where the government does not own much outright, but it plans and regulates the economy
Indicate whether the statement is true or false.
What process gives trenches their unique arc-shaped depressions?
a. Spreading b. Volcanic eruptions c. Subduction d. Turbidity e. Erosion
Who is responsible for the consumption of approximately a quarter of the global oil supply?
A) China B) United States C) India D) United Kingdom