Please answer this: I have a new situation: David was studying human history. He selected two specific eras of human history, era A and era B. Era A was before humans had invented agriculture. And, era B was after the invention of agriculture. He noticed that human societies had changed dramatically after the invention of agriculture. But I can use this background: Human beings invented agriculture about 10,000 years ago. This provided a bigger, more dependable food supply. It also allowed people to settle down in villages and cities for the first time. Birth rates went up because there was more food and settled life had other advantages. Death rates also rose because of crowded living conditions and diseases that spread from domestic animals. Because the higher birth rates were matched by higher death rates, the human population continued to grow very slowly. What is an answer for this question: Which era saw lower death rate, era A or era B?
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Answer: era A

Please answer this: I have a new situation: Two regions, region A and region B, shared a common border, a river. Region A was favorable for sulfate-reducing bacteria and nitrogen fixing bacteria, while region B was more favorable for the developement of Non-respiratory anaerobes and facultative anaerobes. But I can use this background: In many ways, bacterial metabolism provides traits that are useful for ecological stability and for human society. One example is that some bacteria have the ability to fix nitrogen gas using the enzyme nitrogenase. This environmentally important trait can be found in bacteria of most metabolic types listed above. This leads to the ecologically important processes of denitrification, sulfate reduction, and acetogenesis, respectively. Bacterial metabolic processes are also important in biological responses to pollution; for example, sulfate-reducing bacteria are largely responsible for the production of the highly toxic forms of mercury (methyl- and dimethylmercury) in the environment. Non-respiratory anaerobes use fermentation to generate energy and reducing power, secreting metabolic by-products (such as ethanol in brewing) as waste. Facultative anaerobes can switch between fermentation and different terminal electron acceptors depending on the environmental conditions in which they find themselves. What is an answer for this question: Which region had less denitrification?
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Answer: region B

Please answer this: I have a new situation: Brad and Henry were two old friends in their 70's. Brad had very high levels of cholesterol, while Henry was healthier and had normal levels of cholesterol. But I can use this background: Currently, millions of individuals with high cholesterol take a similar type of drug, known as a statin. The drug, an inhibitor of HMG-CoA reductase (3-hydroxy-3-methyl-glutaryl-CoA reductase), the rate limiting enzyme in cholesterol biosynthesis, decreases blood levels of cholesterol by induce the expression of low density lipoprotein (LDL) receptors in the liver. The increased levels of the LDL-receptors stimulate the catabolism of plasma LDL, removing cholesterol from plasma, which is an important determinant of atherosclerosis. You may know of people who take a statin to help with their cholesterol levels. However, these drugs probably work slightly differently in many of those people. In some, it lowers their cholesterol significantly; in others it may lower it only moderately; and in some, it may have no significant effect at all. (Luckily for those individuals, there are multiple versions of the statins, so different drugs can be tested to find the proper combination for that individual.) Why the difference? Because of the genetic background of all people; the different single nucleotide polymorphisms that make us all different. Pharmacogenomics, a combination of pharmacology and genomics (the study of the genome) that refers to the study of the relationship between pharmaceuticals and genetics, may explain and simplify this problem. What is an answer for this question: Which friend does not take a drug that removes cholesterol from plasma?
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Answer:
Henry