| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.00 |
| Score | 0% | 60% |
The __________ is a system of muscles that allows breathing.
pulmonary |
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trachea |
|
bronchioles |
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diaphragm |
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.
The pitch of the siren of an approaching ambulance changes as it approaches you. This is an example of which of the following?
Doppler effect |
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reflection |
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refraction |
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sound radiation |
The Doppler effect occurs when the source or listener (or both) of sound waves is moving. If they're moving closer together, the listener perceives the sound with a higher pitch and, when they're moving apart, the listener perceives the sound with a lower pitch.
The two heart chambers that pump blood called:
atria |
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ventricles |
|
aorta |
|
valves |
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.
In the food chain, omnivores may be which of the following?
primary or tertiary consumers |
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primary or secondary consumers |
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secondary consumers or scavengers |
|
secondary or tertiary consumers |
Secondary or tertiary consumers may be omnivores.
Veins __________ blood at __________ pressure.
deoxygenated, high |
|
oxygenated, high |
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deoxygenated, low |
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oxygenated, 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.