| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.47 |
| Score | 0% | 69% |
The rate of vibration of sound is called:
amplitude |
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frequency |
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period |
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volume |
The rate of vibration of sound is called frequency and is measured in hertz (Hz). One hertz is one repetition per second and sounds with high frequency have a higher pitch than sounds with lower frequency. Humans can hear sounds in the range of 20 Hz to 20 kHz.
DNA is encoded through a combination of which of the following?
nucleotides |
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helix |
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genes |
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gametes |
Deoxyribonucleic acid (DNA) is the molecule that contains genetic information. DNA is encoded through a combination of nucleotides that bind together in a specific double helix pattern.
The __________ is a system of muscles that allows breathing.
bronchioles |
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trachea |
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pulmonary |
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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.
In the food chain, consumers are classified as which of the following?
tertiary |
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primary |
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secondary |
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all of these |
Most animals consume other organisms to survive. Consumers (heterotrophs) are divided into three types, primary, secondary, and tertiary, based on their place in the food chain.
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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sound radiation |
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refraction |
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reflection |
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.