Given the background: Rain dissolves fertilizer in the soil. Runoff carries it away. The fertilizer ends up in bodies of water, from ponds to oceans. Nitrogen is a fertilizer in the water. Since there is a lot of nitrogen, it causes algae to grow out of control. Pictured below is a pond covered with algae ( Figure below ). Algae use up carbon dioxide in the water. After the algae die, decomposers break down the dead tissue. The decomposers use up all the oxygen in the water. This creates a dead zone. A dead zone is an area in a body of water where nothing grows because there is too little oxygen. There is a large dead zone in the Gulf of Mexico ( Figure below ). The U.S. states outlined on the map have rivers that drain into the Gulf of Mexico. The rivers drain vast agricultural lands. The water carries fertilizer from these areas into the Gulf. and the situation: Two neighboring towns from Texas produced their food in different ways. Silver town was sustainable and didn't use any fertilizers or pesticides, while Gold town did. Answer the following question: Which town didn't play a part in causing a large dead zone in the Gulf of Mexico ?
Ans: Silver

Given the background: The water level is seasonal, being lowered by about 10 feet (3.0 m) over the winter. The reservoir fills in the spring from snow melt and underground springs. The lake is usually at full level by late spring, but in the occasional years of low snow melt and low rainfall, it may remain up to several feet below its typical level. Water is let out of the lake in the fall so that ice will not damage docks and other structures around the lake. This also leads to excellent water quality, as a significant portion of the water is replaced every year. and the situation: The water level in Large Lake was high in March, 3 feet higher in April, and 7 feet higher still in May. It dropped to a much lower level in September, October and November, when they released a significant portion of the water as a yearly chore. Answer the following question: When was the water level higher, in March or in May?
Ans: in May

Given the background: Animals and some bacteria and fungi carry out lactic acid fermentation. Lactic acid is a waste product of this process. Our muscles perform lactic acid fermentation during strenuous exercise, since oxygen cannot be delivered to the muscles quickly enough. The buildup of lactic acid is believed to make your muscles sore after exercise. Bacteria that produce lactic acid are used to make cheese and yogurt. The lactic acid causes the proteins in milk to thicken. Lactic acid also causes tooth decay, because bacteria use the sugars in your mouth for energy. and the situation: Mark and Jerry are brothers. Mark just got done working out and returned home to find his brother laying down on the couch eating a bag of potato chips. Mark comments that Jerry should really come and work out with him some time. Jerry brushes him aside. Answer the following question: Which person's muscles are not getting enough oxygen?
Ans: Mark

Given the background: In the U.S., the majority of electricity is produced by burning coal or other fossil fuels. This causes air pollution, acid rain, and global warming. Fossil fuels are also limited and may eventually run out. Like fossil fuels, radioactive elements are limited. In fact, they are relatively rare, so they could run out sooner rather than later. On the other hand, nuclear fission does not release air pollution or cause the other environmental problems associated with burning fossil fuels. This is the major advantage of using nuclear fission as a source of energy. and the situation: Marion county used coal and oil to produce electricity, while James county used nuclear energy for its electricity production. Both counties had a flourishing economy. Answer the following question: Which county caused more global warming?
Ans: Marion