Problem: 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. 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. Which farmer observed decreased leaching of weathering products in the soil?

A: Bill

Problem: HIV , or human immunodeficiency virus, causes AIDS. AIDS stands for "acquired immune deficiency syndrome." It is a condition that causes death and does not have a known cure. AIDS usually develops 10 to 15 years after a person is first infected with HIV. The development of AIDS can be delayed with proper medicines. The delay can be well over 20 years with the right medicines. Today, individuals who acquire HIV after 50 years of age can expect to reach an average human life span. Two college buddies have known each other for 20 years. Tim was HIV positive while John was not and he didn't have a problem with it. Which friend has a greater chance of developing AIDS?

A: Tim

Problem: Insecticide control of aphids is difficult, as they breed rapidly, so even small areas missed may enable the population to recover promptly. Aphids may occupy the undersides of leaves where spray misses them, while systemic insecticides do not move satisfactorily into flower petals. Finally, some aphid species are resistant to common insecticide classes including carbamates, organophosphates, and pyrethroids.For small backyard infestations, spraying plants thoroughly with a strong water jet every few days may be sufficient protection. An insecticidal soap solution can be an effective household remedy to control aphids, but it only kills aphids on contact and has no residual effect. Soap spray may damage plants, especially at higher concentrations or at temperatures above 32 C (90 F); some plant species are sensitive to soap sprays. Bill and Jane are two farmers. They both had aphid infestation problems over the last few years, so Bill decided to use many types of insecticides in order to keep the aphids under control. He was only partially successful. Jane didn't do anything about it yet, because she has fewer aphids on her farm, but she vows to do so in the near future. Which farmer had fewer aphids resistant to common insecticide?

A: Jane

Problem: Some materials have negative heats of solution; the dissolution of one of these solutes in water is an exothermic process. Heat is released, causing a net increase in the temperature of the solution. Conversely, other substances have positive heats of solution. For example, the dissolution of potassium nitrate in water is an endothermic process. The resulting absorption of energy causes the solution to become colder. Calculations involving heats of solutions follow the same basic approach that we have used with other enthalpy problems. John is conducting an experiment in his chemistry lab. His goal is to find a chemical solution that can regulate temperature. To that end, he considered two processes, process A and process B. Process A is an exothermic process, but process B is an endothermic process. Which process would involve negative heats of solution, process A or process B?

A:
process A