| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.39 |
| Score | 0% | 68% |
Which of the following is not a medium for sound waves?
vacuum |
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none of these is a medium for sound waves |
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liquid |
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solid |
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.
Which of these layers is found directly below the Earth's crust?
inner core |
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outer core |
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mantle |
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continents |
The crust is the Earth's outermost layer and is divided into oceanic and continental types. Oceanic crust is 3 miles (5 km) to 6 miles (10 km) thick and is composed primarily of denser rock. Continental crust is 20 to 30 miles (30 to 50 km) thick and composed primarily of less dense rock. The crust makes up approximately one percent of the Earth's total volume.
Which of the following describes the Earth's mantle?
primarily liquid |
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primarily solid |
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liquid |
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solid |
Mantle makes up 84% of the Earth's volume and has an average thickness of approximately 1,800 miles (2,900 km). It is dense, hot, and primarily solid although in places it behaves more like a viscous fluid as the plates of the upper mantle and crust gradually "float" along its circumference.
A person's genotype is their genetic makeup and includes:
phenotypes |
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recessive alleles |
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dominant alleles |
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both dominant and recessive alleles |
A person's genotype is their genetic makeup and includes both dominant and recessive alleles. Phenotype is how the genes express themselves in physical characteristics.
Herbivores are __________ that subsist on producers like plants and fungus.
primary consumers |
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scavengers |
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secondary consumers |
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tertiary consumers |
Primary consumers (herbivores) subsist on producers like plants and fungus. Examples are grasshoppers, cows, and plankton.