There is more gold in 1 km3 of the ocean than the amount of gold mined in all of recorded history. How come we do not mine the oceans?
A. It would cost too much.
B. It is too dilute to separate.
C. It would take too much energy.
D. all of the above
E. none of the above
Answer: D
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According to the Stockholm Environment Institute, which of the following boundaries on which human survival depends may have already been crossed by humans?
A) Ocean acidification and stratospheric ozone depletion B) Freshwater use and chemical pollution C) Climate change, biodiversity loss, and nutrient cycle disruptions D) Land system change, chemical pollution, and ozone depletion
During the light reactions of photosynthesis, the solar energy absorbed by chlorophyll is used to ________
A) split water molecules and release oxygen in the form of O2 B) defend against predators C) produce small, high-energy molecules that are used in the Calvin cycle to manufacture sugars D) break down macromolecules such as starch E) Both A and C
Production of which of the following is expected to decline around the middle of this century, as global deposits dwindle?
A) Carbon dioxide B) Reactive sulfur C) Phosphorus fertilizer D) Nitrogen fertilizer
What is the difference between faults and joints?
A) Joints are the result of compression, whereas faults are the result of tension. B) Joints are the result of earthquakes, and faults are the result of weathering. C) Joints form in place, whereas faults form because rock has moved. D) Joints form from external stress, and faults form from cooling.