Which of the following is not true of solar energy?
A) The United States receives as much energy in 35 minutes of insolation as we produce by burning fossil fuels in the United States in a year.
B) It can provide both heat and electricity.
C) Photovoltaic capacity has not increased in recent years.
D) Experimental photovoltaic cells have broken the 40 efficiency barrier.
Question 2
Which of the following human activities may make soils more prone to erosion?
A) overcultivation
B) overgrazing
C) forest clearance
D) overcultivation, overgrazing,and forest clearance may all make soils more prone to erosion