| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.74 |
| Score | 0% | 75% |
pH is a scale that measures of how basic or acidic a solution is. A solution with a pH of 4 is:
acidic |
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basic |
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neutral |
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alkaline |
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.
212°F is how many °C?
-100 |
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0 |
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\(135 {5 \over 9}\) |
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100 |
The formula to convert from F° to C° is:
\(C° = {5 \over 9} (F° - 32)\)
plugging in our values gives:
\(C° = {5 \over 9} (212 - 32)\)
\(C° = {5 \over 9} (180) = {{180 \times 5} \over 9}\)
\(C° = {900 \over 9}\)
\(C° = 100\)
Which of the following describes the Earth's mantle?
dense |
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makes up most of Earth's volume |
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hot |
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all of these |
Mantle makes up 84% of the Earth's volume and has an average thickness of approximately 1,800 miles (2,900 km). It is dense, hot, and primarily solid although in places it behaves more like a viscous fluid as the plates of the upper mantle and crust gradually "float" along its circumference.
Plant cells may generate energy through which of the following?
anaerobic respiration |
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all of these |
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aerobic respiration |
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photosynthesis |
Some plant cells produce their own energy through photosynthesis which is the process by which sunlight, carbon dioxide, and water react to make sugar and oxygen. Animal cells cannot produce their own energy and, instead, generate energy when mitochondria consume outside sugar and oxygen through aerobic respiration.
Earth's troposphere layer is which of the following?
farthest from the surface |
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closest to the surface |
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hottest |
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coldest |
The Earth's atmosphere has several layers starting with the troposphere which is closest in proximity to the surface. Containing most of the Earth's breathable air (oxygen and nitrogen), it's a region with warmer temperatures closer to the surface and cooler temperatures farther away which results in the rising and falling air that generates weather.