| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.52 |
| Score | 0% | 70% |
The coldest point in the Earth's atmosphere is reached in which atmospheric layer?
thermosphere |
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mesosphere |
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stratosphere |
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troposphere |
In the mesosphere, temperature again drops as altitude increases until the coldest point in the Earth's atmosphere, the mesopause, is reached where temperatures fall to −225 °F (−143 °C).
What is a major difference between the somatic and autonomic nervous systems?
one controls voluntary activity, one controls involuntary activity |
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one controls thinking, the other controls feeling |
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one is inherited, the other is learned |
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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.
This skeletal system is common in arthropods like insects, spiders, and crustaceans.
vertebrate |
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endoskeleton |
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bone |
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exoskeleton |
An exoskeleton (external skeleton) is common in arthropods like insects, spiders, and crustaceans.
Leafy vegetables, beans, potatoes, fruits, and whole grains are good sources of:
unsaturated fat |
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fiber |
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protein |
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saturated fat |
Fiber provides bulk to help the large intestine carry away waste. Good sources of fiber are leafy vegetables, beans, potatoes, fruits, and whole grains.
The two heart chambers that collect blood are called:
aorta |
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valves |
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atria |
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ventricles |
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.