Which of these human activities is most likely to cause an increase in the number of cases of heat exhaustion among humans? a. increased consumption of beef, which increases methane production b. use of solar panels instead of fossil fuels for energy production c. burning of plastics in open burn barrels d. use of hair spray containing chlorofluorocarbons

The appropriate answer is a. Increased consumption of beef which increases methane production. Increases in the number of cases of heat exhaustion will be caused by increases in temperature as a result of the exacerbation of the greenhouse effect which leads to global warming. Cattle production produces large quantities of methane as a result of the process of digestion in these animals. Methane, like carbon dioxide is a greenhouse gas however it traps more heat than carbon dioxide. Methane production as a result of livestock rearing will be the cause of the increased cases because it is practiced on a very large scale. Burning plastics and using cfcs do release greenhouse gases but on a much smaller scale. 
Using solar panels instead of fossil fuels will actually reduce the greenhouse gases if done on a large scale.