The lungs of mammals are unique in having alveoli . These are tiny, sac-like structures. Each alveolus is surrounded by a network of very small blood vessels (see Figure below ). Because there are millions of alveoli in each lung, they greatly increase the surface area for gas exchange between the lungs and bloodstream. Human lungs, for example, contain about 300 million alveoli. They give the lungs a total surface area for gas exchange of up to 90 square meters (968 square feet). That's about as much surface area as one side of a volleyball court! Two groups of students studied Biology. Group One studied mammals, while Group Two studied birds. They focused on the respiratory system. Which group of students learned less about alveoli being surrounded by a network of very small blood vessels ?
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Answer: Two

Q: All machines make work easier, but they don't increase the amount of work that is done. You can never get more work out of a machine than you put into it. In fact, a machine always does less work on an object than the user does on the machine. That's because a machine must use some of the work put into it to overcome friction. Friction is the force that opposes motion between any surfaces that are touching. All machines involve motion, so they all have friction. How much work is needed to overcome friction in a machine depends on the machine's efficiency. During the summer Anthony found it was way too hot to be comfortable. He went out to his garage to get an old fan. The fan was spins on a metal bearing but because it is old it was slightly rusted. When he turned the fan on it spun very slow, struggling to move. He then decided to lubricate the bearing that rotates the fan blades and the fan started spinning normally. Given that Adam decided to tighten the bearing in his fan will the work it requires to operate increase or decrease?
A: increase

Question: Active transport occurs when a substance passes through the cell membrane with the help of extra energy. This happens when a substance moves from an area where it is less concentrated to an area where it is more concentrated. This is the opposite of diffusion. The substance moves up, instead of down, the concentration gradient. Like rolling a ball uphill, this requires an input of energy. The energy comes from the molecule named ATP (adenosine triphosphate). The energy allows special transport proteins called pumps to move substances to areas of higher concentration. An example is the sodium-potassium pump. Two cells, Cell B and Cell C, are being examined under microscopes by students in a science class. While looking at the cells, one student, Kim, notices that there is a noticeable trend in Cell B for a particular substance to try to group up in a more concentrated area. In Cell C though, she notices that the same substance is spreading apart and finding less concentrated areas to move to. Which cell is exhibiting active transport?
Answer: Cell B

[Q]: Predators play an important role in an ecosystem. For example, if they did not exist, then a single species could become dominant over others. Grazers on a grassland keep grass from growing out of control. Predators can be keystone species . These are species that can have a large effect on the balance of organisms in an ecosystem. For example, if all of the wolves are removed from a population, then the population of deer or rabbits may increase. If there are too many deer, then they may decrease the amount of plants or grasses in the ecosystem. Decreased levels of producers may then have a detrimental effect on the whole ecosystem. In this example, the wolves would be a keystone species. Two teams studied two types of animals: team A studied predators, while team B studied grazers. They learned a lot from this experience. Which team didn't learn about keystone species?
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[A]: team B

input: Please answer the following: 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. Two teams of researchers studied different diseases. team Alpha studied people with cholesterol, while team Beta studied people with Parkinson's disease. Which team studied more people with high blood pressure?
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output: Alpha

Clouds on Earth are made of water vapor. Venus's clouds are a lot less pleasant. They are made of carbon dioxide, sulfur dioxide and large amounts of corrosive sulfuric acid! The atmosphere of Venus is so thick that the pressure on the surface of Venus is very high. In fact, it is 90 times greater than the pressure at Earth's surface! The thick atmosphere causes a strong greenhouse effect. As a result, Venus is the hottest planet. Even though it is farther from the Sun, Venus is much hotter even than Mercury. Temperatures at the surface reach 465C (860F). That's hot enough to melt lead! Two friends studied different planets for their school project. Sean studied Earth's atmosphere, while Bill studied Venus's and Mercury's. Which friend studied more about clouds made of water vapor?
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Answer:
Sean