Question: I have a new situation: Two sister cities used different methods to produce electricity. London used fossil fuels, while Edmonton use entirely hydro power to generate energy. But I can use this 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. What is an answer for this question: Which city causes less acid rain?
Answer: Edmonton

Question: I have a new situation: During the summer Anthony found it was way too hot to be comfortable. He went out to his garage to get an old fan. The fan was spins on a metal bearing but because it is old it was slightly rusted. When he turned the fan on it spun very slow, struggling to move. He then decided to lubricate the bearing that rotates the fan blades and the fan started spinning normally. But I can use this background: All machines make work easier, but they don't increase the amount of work that is done. You can never get more work out of a machine than you put into it. In fact, a machine always does less work on an object than the user does on the machine. That's because a machine must use some of the work put into it to overcome friction. Friction is the force that opposes motion between any surfaces that are touching. All machines involve motion, so they all have friction. How much work is needed to overcome friction in a machine depends on the machine's efficiency. What is an answer for this question: Will reducing the friction in a machine make the machine require more or less work?
Answer: less

Question: I have a new situation: Two brothers have a piece of land each, situated 2 miles from each other. Jim's land is not very fertile because it has clay soil with a high pH, while Bob's land has very fertile soil and has a good productivity on it. But I can use this background: Alkali, or Alkaline, soils are clay soils with high pH (> 8.5), a poor soil structure and a low infiltration capacity. Often they have a hard calcareous layer at 0.5 to 1 metre depth. Alkali soils owe their unfavorable physico-chemical properties mainly to the dominating presence of sodium carbonate, which causes the soil to swell[1] and difficult to clarify/settle. They derive their name from the alkali metal group of elements, to which sodium belongs, and which can induce basicity. Sometimes these soils are also referred to as alkaline sodic soils. Alkaline soils are basic, but not all basic soils are alkaline. What is an answer for this question: Which of the two pieces of land has a low filtration capacity?
Answer:
Jim's