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What are some causes of water pollution?

Water pollution refers to the contamination of natural sources of water such as groundwater, streams, rivers, lakes and oceans due to the introduction of contaminants directly or indirectly into these waters. Polluted water can have serious negative effects to the health of any organism that lives in or drinks this water.\nAs a major global problem, water pollution is known to be the leading cause of diseases and deaths worldwide, accounting for more than 14,000 deaths daily. Since water comprises about 70 percent of the surface of the earth, it's often called the most valuable natural re..

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Why are hurricanes dangerous?

The storm surge often causes more damage than any other part of a hurricane. As a hurricane moves closer to the shoreline, winds force water toward the shore. When the storm reaches shallower waters near the coast, a great deal of water piles up. When a storm's eye lands, the force of the hurricane's winds push tons of water onto land that can easily destroy many structures.\nDuring a hurricane's landfall, 5 to 10 inches of rain can often fall. Large storms or storms that move slowly can drop even more rain on an area. Hurricane rains can cause flooding that is not only limited ..

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What is the anterior horn cell?

During development, vertebrates experience a differentiation of the spinal column. The anterior or ventral components of the spinal column hold most of the neurons and cells that are responsible for movement. Such cells are called motor neurons. The neurons that travel from the brain to the spinal cord are called upper motor neurons, while the neurons that travel from the spinal cord to the muscles are called lower motor neurons.\nThe posterior or dorsal column develops sensory nerve cells during development. These cells help to transmit information from the extremities to the brain so that th..

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What is the purpose of a ligament?

The anterior cruciate ligament, found at the front of the human knee, is a ligament that athletes frequently injure. Often, it becomes injured when the knee becomes hyperextended or turns inward too far. EhealthMD explains that when this ligament becomes injured, repair often necessitates replacing the entire ligament.\nAccording to Wikipedia, ligaments are composed of collagenous fibers. When they break, they do not normally heal without intervention. Doctors and researchers are beginning to use artificial materials to replace torn, stretched or disconnected ligaments.\nScientists do not unde..

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Is CH4 polar or nonpolar?

Polar molecules contain localized regions of positive and negative charges. Polarity results from the uneven distribution of the molecular electron cloud. Electrons become unevenly distributed when atoms within the molecule have significantly different electronegativity values. Molecular asymmetry can also contribute to polarity. Methane's carbon and hydrogen atoms share the electrons in their bonds almost equally, resulting in only a slight charge differential between the carbon and hydrogen atoms. Methane's symmetric, tetrahedral geometry also contributes to its lack of polarity.

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What are some ideas for an egg drop experiment?

The cereal method requires several plastic bags and a generous quantity of cereal. Students place the egg in one small bag surrounded by cereal. Next, they fill four or five other small bags with cereal. Finally, the experimenters place all the small bags in a larger bag, with the bag holding the egg situated in the center, cushioned from impact.\nWith the pantyhose method, students cut off one leg of hose and insert the egg into the center, securing it with a rubber band at each end of the egg. The students then stretch the hose tightly and staple the material across the top of an empty box, ..

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Where does the sun's energy come from?

The fusion of hydrogen atoms into helium releases energy because the mass of helium formed is slightly less than the mass of the original hydrogen atoms. This extra mass is converted into energy. Einstein's equation E = mc^2 depicts this energy-releasing process.\nThe energy radiating outward balances the gravitational force wanting to crush the sun. Only under conditions of extreme temperature and pressure, such as those found within the core of the sun, can nuclear fusion reactions happen. Once all the hydrogen atoms in the sun's core are fused into helium atoms, the star begins to..

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What is the net charge of the ionic compound calcium fluoride?

The chemical formula for calcium fluoride is CaF2. It is a crystalline solid that is commonly found in a mineral called fluorite or fluorspar. It has a molar mass of 78.07 grams per mole, a boiling point of 4,591 degrees Fahrenheit and a melting point of 2,584 degrees Fahrenheit. It is used in the production of hydrogen fluoride.

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How many days are in winter?

The seasons were designated to coincide with the natural position of the Earth in relation to the sun and moon, which determines the length of days and nights. Winter begins with the winter solstice, which is when the sun reaches the southernmost point in the sky for those in the Northern Hemisphere or vice versa. It is also the day with the least amount of daylight. From that point, as the sun begins climbing back up in the sky, the amount of daylight increases until the vernal equinox, in which day and night are almost exactly the same length. This is the beginning of spring.

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What are some examples of predator-prey relationships?

A predator is usually a carnivore, and the prey is usually an herbivore, but this is not always the case.\nA predator relies on excellent senses and skills to make a kill. Some of these skills are inherent in the species, and some are acquired. Superior senses of smell, vision and speed are essential for predators.\nThe prey has its own defense mechanism. For example, a cape buffalo has enormous strength to ward off attackers, and a gazelle has speed and stamina to outrun any predator.

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