| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.59 |
| Score | 0% | 72% |
Which of the following substances gives up positively charged hydrogen ions (H+) when dissolved in water?
solution |
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alkaline |
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acid |
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base |
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.
Which of the following describes the Earth's mantle?
dense |
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hot |
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makes up most of Earth's volume |
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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.
Which of blood component fights infection?
red blood cells |
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plasma |
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white blood cells |
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platelets |
Blood is created in bone marrow and is made up of cells suspended in liquid plasma. Red blood cells carry oxygen, white blood cells fight infection, and platelets are cell fragments that allow blood to clot.
When compared to eukaryotic cells, prokaryotic cells are:
similarly complex |
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less complex |
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none of these |
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more 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.
Herbivores are __________ that subsist on producers like plants and fungus.
tertiary consumers |
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scavengers |
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primary consumers |
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secondary consumers |
Primary consumers (herbivores) subsist on producers like plants and fungus. Examples are grasshoppers, cows, and plankton.