| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.31 |
| Score | 0% | 66% |
Water freezing or boiling is an example of which of the following?
sublimation |
|
phase transition |
|
heating |
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cooling |
A substance undergoes a phase transition when it moves from one state of matter to another, for example, when water freezes or boils.
The rate of vibration of sound is called:
frequency |
|
period |
|
amplitude |
|
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.
Which of these foods should a person with high cholesterol avoid?
avocados |
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olive oil |
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eggs |
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vegetable oils |
Fats come in three types, saturated (meats, shellfish, eggs, milk), monounsaturated (olives, almonds, avocados), and polyunsaturated (vegetable oils). Saturated fats can raise LDL ("bad") cholesterol while unsaturated fats can decrease it.
Which of the following substances gives up negatively charged hydroxide ions (OH-) when dissolved in water?
hydrogen |
|
ion |
|
acid |
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base |
An acid is a substance that gives up positively charged hydrogen ions (H+) when dissolved in water. A base (alkaline) gives up negatively charged hydroxide ions (OH-) when dissolved in water. pH is a scale that measures of how basic or acidic a solution is. Numbered from 0 to 14, solutions with a pH of 7 are neutral, less than 7 are acidic, more than 7 are alkaline.
During digestion, the kidneys filter substances from the blood. Which of the following is not filtered by the kidneys?
water |
|
fats |
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minerals |
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salt |
Chemical waste like excess water, minerals, and salt are filtered from the blood by the kidneys and secreted into the urine. Urine is transported from the kidneys to the bladder through ureters.