| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.13 |
| Score | 0% | 63% |
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.
Which of these represents the path of blood flow through the heart?
right atrium → right ventricle → lungs → left atrium → left ventricle |
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right atrium → left ventricle → lungs → left atrium → right ventricle |
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left atrium → right ventricle → lungs → left atrium → right ventricle |
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left atrium → left ventricle → lungs → right atrium → right ventricle |
To provide oxygen to the body, blood flows through the heart in a path formed by the right atrium → right ventricle → lungs → left atrium → left ventricle → body. When blood enters the right side of the heart it is deoxygenated. It enters the left side of the heart oxygenated after traveling to the lungs.
In the metric system, what prefix represents 10-3?
mega |
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kilo |
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centi |
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milli |
In the metric system, milli is the prefix for 10-3.
Which is the proper order of Earth's atmospheric layers from the surface up to space?
troposphere, stratosphere, mesosphere, thermosphere |
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mesosphere, thermosphere, stratosphere, troposphere |
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thermosphere, mesosphere, stratosphere, troposphere |
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stratosphere, troposphere, mesosphere, thermosphere |
The troposphere is the closest layer to Earth, followed by the stratosphere, mesosphere, and finally the thermosphere which borders space.
The asteroids in the Kuiper belt are composed of which of the following?
frozen methane, ammonia, and water |
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rock |
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gaseous methane, ammonia, and water |
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minerals |
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.