A scientist is in the lab testing mixing water with different chemicals. While working with chemical A he notes that the water becomes colder after combining them. With chemical B the water becomes much warmer. Given the changes in temperature, does chemical A cause an exothermic process or an endothermic process? Hint: 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.
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Answer: exothermic

Q: Mike was visiting the African Savannah. One animal that interested him most was the African Buffalo. He noticed that the buffaloes would usually live in a large herd, often exceeding few hundreds. He noted that as case A. But sometimes the buffaloes would live in a small herd. He noted that as case B. Interestingly, there are incidents when an aggressive male buffalo would live by itself. He noted that as case C. In case B, would the group get less or more benefit as a whole than in case A? Hint: A dilution effect is seen when animals living in a group "dilute" their risk of attack, each individual being just one of many in the group. George C. Williams and W.D. Hamilton proposed that group living evolved because it provides benefits to the individual rather than to the group as a whole, which becomes more conspicuous as it becomes larger. One common example is the shoaling of fish. Experiments provide direct evidence for the decrease in individual attack rate seen with group living, for example in Camargue horses in Southern France. The horse-fly often attacks these horses, sucking blood and carrying diseases. When the flies are most numerous, the horses gather in large groups, and individuals are indeed attacked less frequently. Water striders are insects that live on the surface of fresh water, and are attacked from beneath by predatory fish. Experiments varying the group size of the water striders showed that the attack rate per individual water strider decreases as group size increases.
A: more

Question: Bob's parents were in their early 60's. He sent them to the doctor's for a routine check up. Dan, his dad, had very high cholesterol, while Mary, his mom , had normal levels in her blood. Which parent had more cholesterol deposits on the arterial wall? Hint: Cholesterol has been implicated in heart disease for decades. Atherosclerosis is a disorder of the arteries in which cholesterol and other materials are deposited on the interior of the arterial wall. These deposits lead to the formation of plaques that can restrict or even block the flow of blood through these blood vessels (see Figure below ). A decrease in the flow of blood can lead to high blood pressure and a lowered oxygen supply to the heart muscle. A complete blockage of blood flow to parts of the heart (a heart attack) can cause significant damage due to oxygen deprivation, in some cases leading to death.
Answer: Dan

[Q]: Two neighboring planets identical to Earth in size and atmospheric conditions behaved differently towards their environments. Planet A emitted a lot of air pollution, destroying its ozone layer, while Planet B respected the environment and used ecological products. Which planet had higher levels of UV reaching it? Hint: Unfortunately, the layer of good ozone is being destroyed by air pollution. The chief culprits are chlorine and bromine gases. They are released in aerosol sprays, coolants, and other products. Loss of ozone has created an ozone hole over Antarctica. Ozone depletion results in higher levels of UV radiation reaching Earth. In humans, this increases skin cancers and eye cataracts. It also disturbs the nitrogen cycle, kills plankton, and disrupts ocean food webs. The total loss of the ozone layer would be devastating to most life. It's rate of loss has slowed with restrictions on pollutants, but it is still at risk.
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[A]: Planet A

input: Please answer the following: There are two cells inside a Petri dish in a laboratory, cell X and cell Z. These cells are from the same organism, but have different characteristics. For example, cell Z is smaller than cell X. Furthermore, scientists studying the two cells have recorded that cell X is more metabolically active than cell Z. Which cell will have more folds throughout the membrane? Hint: As a cell grows, its volume increases more quickly than its surface area. If a cell was to get very large, the small surface area would not allow enough nutrients to enter the cell quickly enough for the cell's needs. This idea is explained in Figure below . However, large cells have a way of dealing with some size challenges. Big cells, such as some white blood cells, often grow more nuclei so that they can supply enough proteins and RNA for the cell's requirements. Large, metabolically active cells often have lots of cell protrusions, resulting in many folds throughout the membrane. These folds increase the surface area available for transport of materials into or out of the cell. Such cell types are found lining your small intestine, where they absorb nutrients from your food through protrusions called microvilli .
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output: cell X

Robert and Justin are both patients in the hospital who are suffering complications from their HIV infections. The doctor is trying to get information from both men about their diseases so he can create customized treatment plans for both men. After a few questions, the doctor discovers that Robert has been infected with HIV for many years, while Justin's infection is quite recent. Who will have a smaller number of T cells in their body? Hint: As time passes, the number of HIV copies keeps increasing, while the number of helper T cells keeps decreasing. The graph in Figure below shows how the number of T cells typically declines over a period of many years following the initial HIV infection. As the number of T cells decreases, so does the ability of the immune system to defend the body. As a result, an HIV-infected person develops frequent infections. Medicines can slow down the virus but not get rid of it, so there is no cure at present for HIV infections or AIDS. There also is no vaccine to immunize people against HIV infection, but scientists are working to develop one.
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Answer:
Robert