Problem: I read this background article the other day: In the U.S., the majority of electricity is produced by burning coal or other fossil fuels. This causes air pollution that harms the health of living things. The air pollution also causes acid rain and contributes to global warming. In addition, fossil fuels are nonrenewable resources, so if we keep using them, they will eventually run out. The main advantage of nuclear energy is that it doesn’t release air pollution or cause the other environmental problems associated with the burning of fossil fuels. On the other other hand, radioactive elements are nonrenewable like fossil fuels and could eventually be used up.  I am facing a new situation today: Canada produced its electricity by using fossil fuels and nuclear fission. New Zealand used only alternative, renewable sources to produce their electricity.  Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which country burned more coal?

A: Canada


Problem: I read this background article the other day: When soil is flooded, hypoxia develops, as soil microorganisms consume oxygen faster than diffusion occurs. The presence of hypoxic soils is one of the defining characteristics of wetlands. Many wetland plants possess aerenchyma, and in some, such as water-lilies, there is mass flow of atmospheric air through leaves and rhizomes. There are many other chemical consequences of hypoxia. For example, nitrification is inhibited as low oxygen occurs and toxic compounds are formed, as anaerobic bacteria use nitrate, manganese, and sulfate as alternative electron acceptors. The reduction-oxidation potential of the rhizhosphere decreases and metal ions such as iron and manganese precipitate. Aerenchyma is a modification of the parenchyma.  I am facing a new situation today: United States has varied geographical characteristics. Take for example, the Mississippi Delta. The delta has vast wetland that gets inundated every year. On the contrary, farther west, the Mojave Desert in Nevada sees very little precipitation or floodwater. Both places are beautiful in their own right, and attract many tourists every year.  Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: In which place less metal ions would precipitate, Mississippi Delta or Mojave Desert?

A: Mojave Desert


Problem: I read this background article the other day: During May, June, and July, the Northern Hemisphere is exposed to more direct sunlight because the hemisphere faces the Sun. The same is true of the Southern Hemisphere in November, December, and January. It is Earth's axial tilt that causes the Sun to be higher in the sky during the summer months, which increases the solar flux. However, due to seasonal lag, June, July, and August are the warmest months in the Northern Hemisphere while December, January, and February are the warmest months in the Southern Hemisphere.  I am facing a new situation today: Bill has a friend that lives in New Zealand and he always gets confused about the weather and the seasons when they chat, because the Southern Hemisphere has different seasons than people from the Northern Hemisphere.  Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which hemisphere is exposed to more direct sunlight in June?

A: Northern


Problem: I read this background article the other day: In endurance sports such as cycling and running, hitting the wall or the bonk is a condition of sudden fatigue and loss of energy which is caused by the depletion of glycogen stores in the liver and muscles. Milder instances can be remedied by brief rest and the ingestion of food or drinks containing carbohydrates. The condition can usually be avoided by ensuring that glycogen levels are high when the exercise begins, maintaining glucose levels during exercise by eating or drinking carbohydrate-rich substances, or by reducing exercise intensity.  I am facing a new situation today: Two groups of athletes were part of an experiment. Group One ran 10 miles without charging up their body with glycogen at the start of the exercise, and didn't eat or drink other supplements during the race. Group Two did everything by the book and had better overall results.  Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which group had fewer runners experiencing sudden fatigue?

A: