| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.32 |
| Score | 0% | 66% |
The __________ is a system of muscles that allows breathing.
diaphragm |
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bronchioles |
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pulmonary |
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trachea |
The diaphragm is a system of muscles that allows breathing. During inhalation, the diaphragm expands and air rushes in to fill the space created. Then, during exhalation, the diaphragm contracts and forces the air back out.
Cirrus clouds are thin, wispy clouds composed of ice crystals. At what elevation to cirrus clouds form?
ground level |
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low-altitude |
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mid-altitude |
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high-altitude |
Cirrus clouds are thin, wispy high-altitude clouds composed of ice crystals that originate from the freezing of supercooled water droplets. Cirrus clouds generally occur in fair weather and point in the direction of air movement at their elevation.
"The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object." This describes which of Newton's laws of motion?
first |
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second |
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third |
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fourth |
Newton's second law of motion states that The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object. This law basically means that the greater the mass of an object, the more force is needed to overcome its inertia.
Which of the following is the primary difference between a comet and an asteroid?
comets orbit the Sun |
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comets have an atmosphere |
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asteroids have a coma |
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asteroids contain frozen water |
A comet is a loose collection of ice, dust, and small rocky particles that, in contrast to an asteroid, has an extended atmosphere surrounding the center. When passing close to the Sun, this atmosphere warms and begins to release gases forming a visible coma or tail.
The hottest of Earth's atmospheric layers is which of the following?
stratosphere |
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mesosphere |
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troposphere |
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thermosphere |
Temperatures again increase with altitude in the thermosphere which is the hottest (4,530 °F / 2,500 °C) atmospheric layer due to direct exposure to the Sun's radiation. However, the gas in this layer is highly diluted so even though the atoms of gas may be very high in temperature, there are too few of them to effectively transfer much heat.