| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.87 |
| Score | 0% | 57% |
Which of the following does not represent the freezing point of water?
0°C |
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32°F |
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273K |
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0°F |
The Fahrenheit scale fixes the freezing point of water at 32°F, the Celsuis scale at 0°C, and the Kelvin scale at 273K.
Which of the following is the primary difference between a comet and an asteroid?
comets have an atmosphere |
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comets orbit the Sun |
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asteroids contain frozen water |
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asteroids have a coma |
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.
When compared to eukaryotic cells, prokaryotic cells are:
similarly complex |
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none of these |
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more complex |
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less complex |
Cells are classified into one of two groups based on whether or not they have a nucleus. Eukaryotic cells have a nucleus, prokaryotic cells do not have a nucleus and therefore have a less complex structure than eukaryotic cells.
What type of cloud is responsible for fog?
stratus |
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cumulus |
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cumulonimbus |
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cirrus |
Clouds are categorized based on their shape, size, and altitude. Stratus clouds are low-altitude clouds characterized by horizontal layering with a broad flat base. When stratus clouds occur on the ground the result is fog.
pH is a scale that measures of how basic or acidic a solution is. A solution with a pH of 9 is:
alkaline |
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water |
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acidic |
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neutral |
An acid is a substance that gives up positively charged hydrogen ions (H+) when dissolved in water. A base (alkaline) gives up negatively charged hydroxide ions (OH-) when dissolved in water. pH is a scale that measures of how basic or acidic a solution is. Numbered from 0 to 14, solutions with a pH of 7 are neutral, less than 7 are acidic, more than 7 are alkaline.