| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.87 |
| Score | 0% | 57% |
Which of the following is not a medium for sound waves?
liquid |
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solid |
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none of these is a medium for sound waves |
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vacuum |
A vibrating object produces a sound wave that travels outwardly from the object through a medium (any liquid or solid matter). The vibration disturbs the particles in the surrounding medium, those particles disturb the particules next to them, and so on, as the sound propagates away from the vibration.
Examples of primary consumers include:
fish |
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rats |
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cows |
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all of these |
Primary consumers (herbivores) subsist on producers like plants and fungus. Examples are grasshoppers, cows, and plankton.
Scavengers break down the dead bodies of plants and animals into which of the following?
simple nutrients |
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producers |
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complex carbohydrates |
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carrion |
Like decomposers, scavengers also break down the dead bodies of plants and animals into simple nutrients. The difference is that scavengers operate on much larger refuse and dead animals (carrion). Decomposers then consume the much smaller particles left over by the scavengers.
Which of the following substances gives up negatively charged hydroxide ions (OH-) when dissolved in water?
ion |
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base |
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acid |
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hydrogen |
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.
Earth's breathable air is held in which atmospheric layer?
mesosphere |
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stratosphere |
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thermosphere |
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troposphere |
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.