IXL Determine the main idea of a passage questions and answers 100% correct

IXL Determine the main idea of a passage questions and answers 100% correct While excavating a tunnel under Mexico's Naica Mountain, silver miners were stunned to discover a cavern full of luminous, elongated underground crystals. Composed of the mineral gypsum, some of the crystals extended as far as thirty-six feet into the air. What accounted for these amazing mineral structures? Millions of years ago, volcanic eruptions released a large amount of mineral-rich water into the cave, now known as the Cave of Crystals. One of those minerals was anhydrite, which slowly changes into gypsum when exposed to water. Originally, the cave was too hot for this change to take place. Eventually, however, the temperature cooled to about 136°F, and gypsum crystals began to form. This process continued as the temperature and other conditions in the cave remained constant for thousands of years. It identifies a condition that led to the formation of gypsum crystals. Saving the Manatee The Florida manatee, a subspecies of the West Indian manatee, is a large ocean mammal found in Florida's rivers and coastal areas. Unfortunately, the state's population of manatees has dwindled significantly over the years. Although the manatee has no natural predators, humans have contributed to many manatee deaths, mainly through boat collisions. The loss of warm-water habitats has also hastened the manatee's decline. Aerial surveys performed in the early 1990s found an estimated 1,267 manatees in Florida. Because of conservation efforts by several organizations, however, the number of manatees has rebounded recently. The creation of manatee protection zones—areas that boaters must avoid or drive through more slowly—has been particularly effective. As a result of these efforts, more than 6,000 manatees are found in Florida today. Thanks to conservation efforts, Florida manatee populations have increased. Submit Overlooked Women in Science Historically, men have dominated the field of science, and many women have not received professional credit or public recognition for their work. Rosalind Franklin, for example, was a chemist who did groundbreaking research into the structure of DNA, a type of molecule in cells that helps control their growth, activity, and reproduction. Franklin's X-ray photograph of DNA was shared, without her knowledge, with biologist James Watson. Franklin's work helped Watson and fellow researcher Francis Crick discover the structure of DNA, but she received no credit when they won a Nobel Prize for their model of DNA in 1962. Another scientist denied credit for her work was Jocelyn Bell Burnell. Bell was a postgraduate student in 1967 when she discovered the first radio pulsars—small, dense rotating stars that emit radio waves. However, the credit was given to her supervisor, Antony Hewish, who received a Nobel Prize in 1974. Historically, men have dominated the field of science, and many women have not received professional credit or public recognition for their work. Rosalind Franklin, for example, was a chemist who did groundbreaking research into the structure of DNA, a type of molecule in cells that helps control their growth, activity, and reproduction. Franklin's X-ray photograph of DNA was shared, without her knowledge, with biologist James Watson. Franklin's work helped Watson and fellow researcher Francis Crick discover the structure of DNA, but she received no credit when they won a Nobel Prize for their model of DNA in 1962. Another scientist denied credit for her work was Jocelyn Bell Burnell. Bell was a postgraduate student in 1967 when she discovered the first radio pulsars—small, dense rotating stars that emit radio waves. However, the credit was given to her supervisor, Antony Hewish, who received a Nobel Prize in 1974. It describes an incident when a female scientist did not receive credit for her work. The Florida manatee, a subspecies of the West Indian manatee, is a large ocean mammal found in Florida's rivers and coastal areas. Unfortunately, the state's population of manatees has dwindled significantly over the years. Although the manatee has no natural predators, humans have contributed to many manatee deaths, mainly through boat collisions. The loss of warm-water habitats has also hastened the manatee's decline. Aerial surveys performed in the early 1990s found an estimated 1,267 manatees in Florida. Because of conservation efforts by several organizations, however, the number of manatees has rebounded recently. The creation of manatee protection zones—areas that boaters must avoid or drive through more slowly—has been particularly effective. As a result of these efforts, more than 6,000 manatees are found in Florida today. It highlights a successful conservation strategy. Synesthesia: Mixed-Up Senses We generally think of our senses as having completely separate functions. This is a logical assumption; after all, we can't see with our ears or taste with our eyes. For people with a condition called synesthesia, however, senses can be conflated, or mixed together. In fact, the word synesthesia, derived from Greek, literally means "sensations together." This combining of senses causes interesting sensory experiences. For example, some synesthetes (people who experience synesthesia) imagine tasting a particular flavor whenever they hear a certain sound. Others "hear" a sound in their minds whenever they touch a certain object. The most common types of synesthesia involve colors. In one common subtype, for instance, synesthetes associate different colors with different letters of the alphabet. Typically, synesthetes are not bothered by their synesthesia; in fact, many enjoy it. People with synesthesia experience a fusing of different senses. We generally think of our senses as having completely separate functions. This is a logical assumption; after all, we can't see with our ears or taste with our eyes. For people with a condition called synesthesia, however, senses can be conflated, or mixed together. In fact, the word synesthesia, derived from Greek, literally means "sensations together." This combining of senses causes interesting sensory experiences. For example, some synesthetes (people who experience synesthesia) imagine tasting a particular flavor whenever they hear a certain sound. Others "hear" a sound in their minds whenever they touch a certain object. The most common types of synesthesia involve colors. In one common subtype, for instance, synesthetes associate different colors with different letters of the alphabet. Typically, synesthetes are not bothered by their synesthesia; in fact, many enjoy it. It describes the word's origin to reinforce the nature of the condition. Maggots as Medicine While serving in World War I, surgeon William Baer noticed something curious: soldiers whose wounds were infested with maggots (the wormlike immature larval form of flies) recovered faster than those whose wounds were maggot-free. Although Baer was not the first military doctor to take note of this phenomenon, he was the first to apply his observations to the problem of nonhealing wounds. In the 1920s, he began treating hospital patients' serious wounds with maggots. The maggots consumed dead tissue, effectively cleaning the wounds and helping the patients heal. While maggot therapy fell out of favor after bacteria-killing antibiotic medications were introduced, it has made a comeback in modern medicine. Many clinicians have found that the treatment can be effective for certain types of severe wounds that do not respond to antibiotics. As noted by William Baer, some severe wounds can be effectively treated with maggots, which consume dead tissue. While serving in World War I, surgeon William Baer noticed something curious: soldiers whose wounds were infested with maggots (the wormlike immature larval form of flies) recovered faster than those whose wounds were maggot-free. Although Baer was not the first military doctor to take note of this phenomenon, he was the first to apply his observations to the problem of nonhealing wounds. In the 1920s, he began treating hospital patients' serious wounds with maggots. The maggots consumed dead tissue, effectively cleaning the wounds and helping the patients heal. While maggot therapy fell out of favor after bacteria-killing antibiotic medications were introduced, it has made a comeback in modern medicine. Many clinicians have found that the treatment can be effective for certain types of severe wounds that do not respond to antibiotics. It establishes the modern-day relevance of maggot therapy. While excavating a tunnel under Mexico's Naica Mountain, silver miners were stunned to discover a cavern full of luminous, elongated underground crystals. Composed of the mineral gypsum, some of the crystals extended as far as thirty-six feet into the air. What accounted for these amazing mineral structures? Millions of years ago, volcanic eruptions released a large amount of mineral-rich water into the cave, now known as the Cave of Crystals. One of those minerals was anhydrite, which slowly changes into gypsum when exposed to water. Originally, the cave was too hot for this change to take place. Eventually, however, the temperature cooled to about 136°F, and gypsum crystals began to form. This process continued as the temperature and other conditions in the cave remained constant for thousands of years. Specific conditions in the Cave of Crystals led to the development of the enormous crystal structures found there. Sign Language on Martha's Vineyard While researching Martha's Vineyard, an island off the coast of Massachusetts, anthropologist Nora Groce made a remarkable discovery. She learned that from the 1600s until the early 1900s, almost all the residents of two towns on the island—West Tisbury and Chilmark—were fluent in sign language. During these years, the towns had an unusually high population of deaf people, due to a form of hereditary deafness that ran in many Martha's Vineyard families. Consequently, a bilingual society developed. The islanders didn't attend special sign language classes; they simply learned the language as they grew up. One of the most interesting aspects of the phenomenon was that, in the absence of language barriers, deafness was not perceived as a disability. As one Vineyarder explained to Groce, deaf people were seen as "just like everyone else." The high incidence of deafness on Martha's Vineyard While researching Martha's Vineyard, an island off the coast of Massachusetts, anthropologist Nora Groce made a remarkable discovery. She learned that from the 1600s until the early 1900s, almost all the residents of two towns on the island—West Tisbury and Chilmark—were fluent in sign language. During these years, the towns had an unusually high population of deaf people, due to a form of hereditary deafness that ran in many Martha's Vineyard families. Consequently, a bilingual society developed. The islanders didn't attend special sign language classes; they simply learned the language as they grew up. One of the most interesting aspects of the phenomenon was that, in the absence of language barriers, deafness was not perceived as a disability. As one Vineyarder explained to Groce, deaf people were seen as "just like everyone else." It illustrates how natural and widespread the use of sign language was on the island. Fast or Slow? The human brain can be thought of as having two different modes. Daniel Kahneman, an influential psychologist, labels one the "fast" mode of thinking and the other the "slow" mode. In the fast mode, according to Kahneman, we make decisions using our intuitions and emotions. The sight of a spider may activate the fast mode and lead a person to scream. The same person's slow mode might decide (after a moment) that the spider is not actually a threat. In the slow mode, we make decisions using reason and logic. The slow mode is helpful in complex situations where the right choice is not always clear. However, because the slow mode uses more mental resources than the fast mode, our brains can't rely on it all the time. The instincts that drive the fast mode of thinking to save us a great deal of time and energy. The "fast" mode of thinking is helpful for reacting quickly, while the "slow" mode is helpful for analyzing complex situations. The main idea of the passage is The "fast" mode of thinking is helpful for reacting quickly, while the "slow" mode is helpful for analyzing complex situations. How does the detail in bold develop the main idea? The human brain can be thought of as having two different modes. Daniel Kahneman, an influential psychologist, labels one the "fast" mode of thinking and the other the "slow" mode. In the fast mode, according to Kahneman, we make decisions using our intuitions and emotions. The sight of a spider may activate the fast mode and lead a person to scream. The same person's slow mode might decide (after a moment) that the spider is not actually a threat. In the slow mode, we make decisions using reason and logic. The slow mode is helpful in complex situations where the right choice is not always clear. However, because the slow mode uses more mental resources than the fast mode, our brains can't rely on it all the time. The instincts that drive the fast mode of thinking save us a great deal of time and energy. It describes a similarity between the slow and fast modes of thinking. It illustrates the slow mode using a specific example. Read the passage. A Step for Democracy One of the most important years in the history of democracy was 1215, when King John of England signed a document called the Magna Carta. Among other things, the Magna Carta made it illegal to buy or bribe one's way out of legal trouble—previously a common practice. More important, the Magna Carta made it clear that the king of England could not change laws or impose taxes without the people's consent. Because of the Magna Carta, the barons of England, along with civic and church leaders, began having regular meetings with the king to discuss matters such as proposed new taxes. The barons were meant to represent the interests of the people who lived on their land. This practice—revolutionary at the time—laid the groundwork for the modern political system known as representative democracy. Representative democracy allows elected officials to speak for the interests of their constituents, the citizens they represent. The Magna Carta set the stage for democratic governments by affirming the rights of citizens to participate in government. How Fevers Help Fevers can be uncomfortable, but the upside is that they are evidence of the body's attempt to heal. When a person develops an infection, a section of the brain called the hypothalamus recognizes a threat. The hypothalamus responds by increasing the body's temperature. Since both viruses and bacteria are temperature sensitive, this environment helps prevent them from multiplying. In addition, scientists have found evidence that fevers may increase the number of certain lymphocytes—white blood cells that are part of the immune system. Increased lymphocytes make the body more effective in destroying infected cells. Of course, this doesn't mean that high fevers don't warrant medical treatment. In fact, another reason that fevers are beneficial is that they serve as warning signs, indicating that something is amiss. Fevers are useful because they help the body fight infections. Fevers can be uncomfortable, but the upside is that they are evidence of the body's attempt to heal. When a person develops an infection, a section of the brain called the hypothalamus recognizes a threat. The hypothalamus responds by increasing the body's temperature. Since both viruses and bacteria are temperature sensitive, this environment helps prevent them from multiplying. In addition, scientists have found evidence that fevers may increase the number of certain lymphocytes—white blood cells that are part of the immune system. Increased lymphocytes make the body more effective in destroying infected cells. Of course, this doesn't mean that high fevers don't warrant medical treatment. In fact, another reason that fevers are beneficial is that they serve as warning signs, indicating that something is amiss. It points out a weakness of the fever response. It explains the function of lymphocytes in great detail. It describes one manner in which fevers fight infections.