| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.22 |
| Score | 0% | 64% |
The __________ is a system of muscles that allows breathing.
trachea |
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bronchioles |
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diaphragm |
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pulmonary |
The diaphragm is a system of muscles that allows breathing. During inhalation, the diaphragm expands and air rushes in to fill the space created. Then, during exhalation, the diaphragm contracts and forces the air back out.
Veins __________ blood at __________ pressure.
oxygenated, high |
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deoxygenated, high |
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oxygenated, low |
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deoxygenated, low |
Veins carry blood back to the heart from the body. While arteries are thick-walled because they carry oxygenated blood at high pressure, veins are comparatively thin-walled as they carry low-pressure deoxygenated blood. Like the heart, veins contain valves to prevent blood backflow.
Velocity is the rate at which an object changes position. What is the formula for velocity?
\(\vec{v} = { t \over \vec{d} } \) |
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\(\vec{v} = { \vec{d} \over t } \) |
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none of these |
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\(\vec{v} = \vec{d}t \) |
Velocity is the rate at which an object changes position. Rate is measured in time and position is measured in displacement so the formula for velocity becomes \(\vec{v} = { \vec{d} \over t } \)
Which of the following describes the Earth's mantle?
all of these |
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makes up most of Earth's volume |
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hot |
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dense |
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.
In the food chain, omnivores may be which of the following?
primary or secondary consumers |
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primary or tertiary consumers |
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secondary consumers or scavengers |
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secondary or tertiary consumers |
Secondary or tertiary consumers may be omnivores.