user: Problem: 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: Alpine lake had low water levels this spring although the lake is usually at full level by late spring. Last year was a very wet year with lots of precipitation. Rangers were planning on letting water out of the lake in the fall so that ice will not damage docks and other structures around the lake. The water levels were high enough in the fall so they proceeded in lowering the water level by 10 feet..  Answer the following question: When are the lake water levels higher, during winter or during late spring?

A: during late spring


Problem: Given the background: Precipitation in grasslands is equal to or less than evapotranspiration and causes soil development to operate in relative drought. Leaching and migration of weathering products is therefore decreased. Large amounts of evaporation causes buildup of calcium (Ca) and other large cations flocculate clay minerals and fulvic acids in the upper soil profile. Impermeable clay limits downward percolation of water and fulvic acids, reducing chemical weathering and podzolization. The depth to the maximum concentration of clay increases in areas of increased precipitation and leaching. When leaching is decreased, the Ca precipitates as calcite (CaCO3) in the lower soil levels, a layer known as caliche.  and the situation: Two farmers had neighboring parcels of land. Bob had a nice parcel of old growth forest, while the other farmer, named Bill , had a similar sized parcel covered in grasslands.  Answer the following question: Which farmer observed increased migration of weathering products in the soil?

A: Bob


Problem: Given the background: Around 5.4 billion years from now, the core of the Sun will become hot enough to trigger hydrogen fusion in its surrounding shell. This will cause the outer layers of the star to expand greatly, and the star will enter a phase of its life in which it is called a red giant. Within 7.5 billion years, the Sun will have expanded to a radius of 1.2 AU—256 times its current size. At the tip of the red giant branch, as a result of the vastly increased surface area, the Sun's surface will be much cooler (about 2600 K) than now and its luminosity much higher—up to 2,700 current solar luminosities. For part of its red giant life, the Sun will have a strong stellar wind that will carry away around 33% of its mass. During these times, it is possible that Saturn's moon Titan could achieve surface temperatures necessary to support life.As the Sun expands, it will swallow the planets Mercury and Venus. Earth's fate is less clear; although the Sun will envelop Earth's current orbit, the star's loss of mass (and thus weaker gravity) will cause the planets' orbits to move farther out. If it were only for this, Venus and Earth would probably escape incineration, but a 2008 study suggests that Earth will likely be swallowed up as a result of tidal interactions with the Sun's weakly bound outer envelope.Gradually, the hydrogen burning in the shell around the solar core will increase the mass of the core until it reaches about 45% of the present solar mass. At this point the density and temperature will become so high that the fusion of helium into carbon will begin, leading to a helium flash; the Sun will shrink from around 250 to 11 times its present (main-sequence) radius. Consequently, its luminosity will decrease from around 3,000 to 54 times its current level, and its surface temperature will increase to about 4770 K. The Sun will become a horizontal giant, burning helium in its core in a stable fashion much like it burns hydrogen today. The helium-fusing stage will last only 100 million years. Eventually, it will have to...  and the situation: Keith was playing a simulation game. In the game he could travel around the Sun in the future. He started the game in  present time, which was denoted as time A. Then he traveled 5.4 billion years into the future, which was denoted as time B. Finally, he reached 7.5 billion years into the future, which was denoted as time C. He was amazed to find how the Sun would change over time.  Answer the following question: When would the Sun's core be hotter, time A or time B?

A: time B


Problem: 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: Two countries used different methods to produce their energy. Albania used fossil fuels, while Croatia used Nuclear fission.  Answer the following question: Which country caused more global warming?

A:

assistant: Albania