| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.18 |
| Score | 0% | 64% |
This skeletal system is common in arthropods like insects, spiders, and crustaceans.
vertebrate |
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endoskeleton |
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exoskeleton |
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bone |
An exoskeleton (external skeleton) is common in arthropods like insects, spiders, and crustaceans.
The angle of reflection is equal to which the following?
refractive index |
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focal point |
|
angle of incidence |
|
90° |
The law of reflection specifies how waves, including light waves, bounce off of surfaces. Specifically, the angle of incidence of the approaching wave is equal to the angle of reflection of the reflected wave as measured from a line perpendicular (90°) to the surface.
The asteroids in the Kuiper belt are composed of which of the following?
gaseous methane, ammonia, and water |
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minerals |
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frozen methane, ammonia, and water |
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rock |
The Kuiper Belt is similar to the asteroid belt but much larger. Extending beyond the orbit of Neptune, it contains objects composed mostly of frozen methane, ammonia, and water. Most notably, the Kuiper Belt is home to Pluto, a dwarf planet that, until a 2006 reclassification, was considered the ninth planet of the solar system.
pH is a scale that measures of how basic or acidic a solution is. A solution with a pH of 9 is:
neutral |
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acidic |
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alkaline |
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water |
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 substances gives up positively charged hydrogen ions (H+) when dissolved in water?
base |
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acid |
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solution |
|
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.