You are given 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. and a hint : 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. Please answer this question : Which region had more sulfate reduction?
Ans: region A

You are given a new situation: Research team Alpha learned about early human activities, from 200000 years ago, while team Gamma learned about late human activities, 40000 years ago to present times. and a hint : The earliest members of the human species evolved around 200,000 years ago in Africa. Early humans lived in small populations of nomadic hunters and gatherers. Human beings remained in Africa until about 40,000 years ago. After that, they spread throughout Europe, Asia, and Australia. By 10,000 years ago, the first human beings colonized the Americas. During this long period of time, the total number of human beings increased very slowly. Birth rates were fairly high but so were death rates, producing low rates of population growth. Please answer this question : Which team didn't learn about humans that lived in small populations of nomadic hunters?
Ans: team Gamma

You are given 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. and a hint : 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. Please answer this question : Which era saw lower birth rate, era A or era B?
Ans: era A

You are given a new situation: John is a doctor with the local hospital. Earlier today, he was seeing two patients, patient A and patient B. John found out that patient A had more LDL, but patient B had more HDL. He now needs to determine correct treatment for them. and a hint : Cholesterol can't dissolve in the blood. It has to be transported to and from the cells by carriers called lipoproteins. Low-density lipoprotein, or LDL, is known as "bad" cholesterol. High-density lipoprotein (HDL) is known as good cholesterol. When too much LDL cholesterol circulates in the blood, it can slowly build up in the inner walls of the arteries that feed the heart and brain. Together with other substances, it can form plaque, and lead to atherosclerosis. If a clot forms and blocks a narrowed artery, a heart attack or stroke can result. Cholesterol comes from the food you eat as well as being made by the body. To lower bad cholesterol, a diet low in saturated fat and dietary cholesterol should be followed. Regular aerobic exercise also lowers LDL cholesterol and increases HDL cholesterol. Please answer this question : Which patient would more likely risk forming palque, patient A or patient B?
Ans: patient A