| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.18 |
| Score | 0% | 64% |
Which of the following does not represent the freezing point of water?
0°F |
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273K |
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0°C |
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32°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.
The two heart chambers that pump blood called:
valves |
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ventricles |
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atria |
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aorta |
The heart is the organ that drives the circulatory system. In humans, it consists of four chambers with two that collect blood called atria and two that pump blood called ventricles. The heart's valves prevent blood pumped out of the ventricles from flowing back into the heart.
Which of the following substances gives up positively charged hydrogen ions (H+) when dissolved in water?
solution |
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acid |
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alkaline |
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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.
The envelope of gases surrounding the planet is called the:
geosphere |
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lithosphere |
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hydrosphere |
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atmosphere |
The biosphere is the global ecological system integrating all living beings and their relationships. This includes their interactions with the lithosphere (the rigid outer part of the earth, consisting of the crust and upper mantle), hydrosphere (all surface water), and atmosphere (the envelope of gases surrounding the planet).
What is a major difference between the somatic and autonomic nervous systems?
one controls thinking, the other controls feeling |
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one is inherited, the other is learned |
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one controls voluntary activity, one controls involuntary activity |
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each belongs to a different nervous system |
Both are part of the peripheral nervous system. The somatic nervous system sends sensory information to the central nervous system and controls voluntary actions while the autonomic nervous system regulates involuntary activity in the heart, stomach, and intestines.