Q: Declines in population size can result in a loss of genetic diversity, and owing to genetic variation's role in the evolutionary potential of a species, this could in turn result in an observable Allee effect. As a species' population becomes smaller, its gene pool will be reduced in size as well. One possible outcome from this genetic bottleneck is a reduction in fitness of the species through the process of genetic drift, as well as inbreeding depression. This overall fitness decrease of a species is caused by an accumulation of deleterious mutations throughout the population. Genetic variation within a species could range from beneficial to detrimental. Nevertheless, in a smaller sized gene pool, there is a higher chance of a stochastic event in which deleterious alleles become fixed (genetic drift). While evolutionary theory states that expressed deleterious alleles should be purged through natural selection, purging would be most efficient only at eliminating alleles that are highly detrimental or harmful. Mildly deleterious alleles such as those that act later in life would be less likely to be removed by natural selection, and conversely, newly acquired beneficial mutations are more likely to be lost by random chance in smaller genetic pools than larger ones.Although the long-term population persistence of several species with low genetic variation has recently prompted debate on the generality of inbreeding depression, there are various empirical evidences for genetic Allee effects. One such case was observed in the endangered Florida panther (Puma concolor coryi). The Florida panther experienced a genetic bottleneck in the early 1990s where the population was reduced to 25 adult individuals. This reduction in genetic diversity was correlated with defects that include lower sperm quality, abnormal testosterone levels, cowlicks, and kinked tails. In response, a genetic rescue plan was put in motion and several female pumas from Texas were introduced into the Florida population. This action quickly led... Dan is a geneticist and studied two villages from 2,000 years ago. Village A displayed traces of a large population that grew larger over the years, while village B had a small and declining population and was more isolated geographically. Which village experienced a genetic bottleneck?
A: village B

Question: Another example of negative feedback has to do with blood glucose levels. When glucose (sugar) levels in the blood are too high, the pancreas secretes insulin to stimulate the absorption of glucose and the conversion of glucose into glycogen, which is stored in the liver. As blood glucose levels decrease, less insulin is produced. When glucose levels are too low, another hormone called glucagon is produced, which causes the liver to convert glycogen back to glucose. Tim and Fred were two students. Tim studied about negative feedback and the pancreas, while Fred studied about the stomach and the jejunum. Which student read less about glycogen being stored in the liver?
Answer: Fred

[Q]: In exercises such as weight lifting, skeletal muscle contracts against a resisting force (see Figure below ). Using skeletal muscle in this way increases its size and strength. In exercises such as running, the cardiac muscle contracts faster and the heart pumps more blood. Using cardiac muscle in this way increases its strength and efficiency. Continued exercise is necessary to maintain bigger, stronger muscles. If you don't use a muscle, it will get smaller and weakerso use it or lose it. Bill and Bob were two brothers. they were both into physical exercise, but Bill chose weight lifting, and Bob running. Which brother didn't have to do continuous exercise to maintain form?
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[A]: Bob

input: Please answer the following: The dangers of global warming are being increasingly studied by a wide global consortium of scientists. These scientists are increasingly concerned about the potential long-term effects of global warming on our natural environment and on the planet. Of particular concern is how climate change and global warming caused by anthropogenic, or human-made releases of greenhouse gases, most notably carbon dioxide, can act interactively, and have adverse effects upon the planet, its natural environment and humans' existence. It is clear the planet is warming, and warming rapidly. This is due to the greenhouse effect, which is caused by greenhouse gases, which trap heat inside the Earth's atmosphere because of their more complex molecular structure which allows them to vibrate and in turn trap heat and release it back towards the Earth. This warming is also responsible for the extinction of natural habitats, which in turn leads to a reduction in wildlife population.The most recent report from the Intergovernmental Panel on Climate Change (the group of the leading climate scientists in the world) concluded that the earth will warm anywhere from 2.7 to almost 11 degrees Fahrenheit (1.5 to 6 degrees Celsius) between 1990 and 2100. Two identical planets, Norlon and Bothar, have been discovered in a neighboring galaxy of ours. These two planets have the same type of atmosphere as Earth and are extremely similar to Earth in terms of topography and even species of animals that live on them. The main difference is that Norlon is inhabited by a species very similar to humans that emit a lot of carbon dioxide into the atmosphere. Bothar, however, has no such species on its planet. Which of the newly discovered planets will sustain life for a longer amount of time?
++++++++++
output: Bothar

Please answer this: When a solid substance is involved in a chemical reaction, only the matter at the surface of the solid is exposed to other reactants. If a solid has more surface area, more of it is exposed and able to react. Therefore, increasing the surface area of solid reactants increases the reaction rate. Look at the hammer and nails pictured in the Figure below . Both are made of iron and will rust when the iron combines with oxygen in the air. However, the nails have a greater surface area, so they will rust faster. John is trying to figure out how the shape of an object affects how it reacts with other elements. For that, he chose two objects, both made of the same element - object A and object B. Object A has a larger surface area, but object B has smaller surface area. He let these objects to react with other reactants to see how the processes work. Which object would seem react faster, object A or object B?
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Answer: object A

Question: 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. Jacob recently contracted the HIV virus and is going to his first support meeting. While there, he meets Dan and strikes up a conversation with him. Dan says that he has had HIV for over a decade at this point and has learned ways to live with it. He is able to give Jacob some good advice on how to handle things and Jacob is very grateful to have someone to talk with. Who has less T cells, Jacob or Dan?
Answer:
Dan