| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.32 |
| Score | 0% | 66% |
Which of these is not a component of blood?
plasma |
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white blood cells |
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red blood cells |
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marrow |
Blood is created in bone marrow and is made up of cells suspended in liquid plasma. Red blood cells carry oxygen, white blood cells fight infection, and platelets are cell fragments that allow blood to clot.
Stratus clouds are __________clouds characterized by horizontal layering with a broad flat base.
low-altitude |
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high-altitude |
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mid-altitude |
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all-altitude |
Clouds are categorized based on their shape, size, and altitude. Stratus clouds are low-altitude clouds characterized by horizontal layering with a broad flat base. When stratus clouds occur on the ground the result is fog.
The pitch of the siren of an approaching ambulance changes as it approaches you. This is an example of which of the following?
sound radiation |
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reflection |
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Doppler effect |
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refraction |
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 fermentation, what replaces oxygen in anaerobic respiration?
lactic acid or alcohol |
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water |
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starches |
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ascorbic acid or peptides |
If no oxygen is present, cellular respiration is anaerobic and will result in fermentation where either lactic acid or alcohol is used instead of oxygen.
The formula for acceleration is which of the following?
\(\vec{a} = { \vec{F} \over m }\) |
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\(\vec{a} = \vec{F} m\) |
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\(\vec{a} = { m \over F }\) |
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\(\vec{a} = { m \over \vec{F} }\) |
Newton's second law of motion leads to the formula for acceleration which is a measure of the rate of change of velocity per unit time and, if you solve for positive acceleration, reveals how much net force is needed to overcome an object's mass. The formula for acceleration is \(\vec{a} = { \vec{F} \over m }\) or, solving for force, \(\vec{F} = m\vec{a}\).