| 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?
32°F |
|
0°F |
|
273K |
|
0°C |
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 pitch of the siren of an approaching ambulance changes as it approaches you. This is an example of which of the following?
reflection |
|
refraction |
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Doppler effect |
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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.
In the pancreas, lipase converts fat to:
simple sugars |
|
amino acids |
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glycerol and fatty acids |
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complex carbohydrates |
The acids produced by the pancreas contain several enzymes that aid in digestion. Lipase converts fat to glycerol and fatty acids. Pancreatic amylase breaks down complex carbohydrates into simple sugars. Trypsin converts polypeptides (the building blocks of protein) into amino acids.
Scavengers break down the dead bodies of plants and animals into which of the following?
simple nutrients |
|
complex carbohydrates |
|
producers |
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carrion |
Like decomposers, scavengers also break down the dead bodies of plants and animals into simple nutrients. The difference is that scavengers operate on much larger refuse and dead animals (carrion). Decomposers then consume the much smaller particles left over by the scavengers.
A major difference between sound waves and light waves is which of the following?
all of these are correct |
|
a sound wave is much slower than a light wave |
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a sound wave cannot travel through a vacuum |
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a sound wave is mechanical while a light wave is electromagnetic |
A vibrating object produces a sound wave that travels outwardly from the object through a medium (any liquid or solid matter). The vibration disturbs the particles in the surrounding medium, those particles disturb the particules next to them, and so on, as the sound propagates away from the vibration.