| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.48 |
| Score | 0% | 70% |
Which of blood component allows blood to clot?
plasma |
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platelets |
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red blood cells |
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white blood cells |
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.
The hottest of Earth's atmospheric layers is which of the following?
thermosphere |
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mesosphere |
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troposphere |
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stratosphere |
Temperatures again increase with altitude in the thermosphere which is the hottest (4,530 °F / 2,500 °C) atmospheric layer due to direct exposure to the Sun's radiation. However, the gas in this layer is highly diluted so even though the atoms of gas may be very high in temperature, there are too few of them to effectively transfer much heat.
Which of the following is not a vector quantity?
momentum |
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acceleration |
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mass |
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velocity |
Velocity and displacement are vector quantities which means each is fully described by both a magnitude and a direction. In contrast, scalar quantities are quantities that are fully described by a magnitude only. A variable indicating a vector quantity will often be shown with an arrow symbol: \(\vec{v}\)
Poor balance could indicate an issue with which part of the nervous system?
medulla |
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cerebrum |
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cerebellum |
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spinal cord |
The cerebellum is a large cluster of nerves at the base of the brain that's responsible for balance, movement, and muscle coordination.
Vector quantities are fully described by which of the following?
a magnitude and a direction |
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a direction and a polarity |
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a magnitude only |
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a direction only |
Velocity and displacement are vector quantities which means each is fully described by both a magnitude and a direction. In contrast, scalar quantities are quantities that are fully described by a magnitude only. A variable indicating a vector quantity will often be shown with an arrow symbol: \(\vec{v}\)