| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.17 |
| Score | 0% | 63% |
Which of the following states of matter exists at the lowest temperature?
none of these |
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solid |
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gas |
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liquid |
Solids exist at a lower temperature than liquids which exist at a lower temperature than gases.
The hottest of Earth's atmospheric layers is which of the following?
stratosphere |
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troposphere |
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thermosphere |
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mesosphere |
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.
Which of the following is not part of the carbon cycle?
photosynthesis |
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precipitation |
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respiration |
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decomposition |
The carbon cycle represents the ciruit of carbon through Earth's ecosystem. Carbon dioxide (CO2) in the atmosphere is absorbed by plants through photosynthesis. Plants then die and release carbon back into the atmosphere during decomposition or are eaten by animals who breathe (respiration) the carbon into the atmosphere they exhale and produce waste which also releases carbon as it decays.
Which of the following is the formula for power?
\(P = \vec{w}t\) |
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\(P = w t\) |
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\(P = {w \over t}\) |
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\(P = {\vec{w} \over t}\) |
Power is the rate at which work is performed or work per unit time: \(P = {w \over t}\) and is measured in watts (W).
The process of diffusion allows __________ to exchange oxygen, carbon dioxide, nutrients, and waste between blood and the body's cells.
capillaries |
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veins |
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red blood cells |
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arteries |
Capillaries are small thin-walled vessels that permit the exchange of oxygen, carbon dioxide, nutrients, and waste between blood and the body's cells. This process of exchange is called diffusion.