| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.44 |
| Score | 0% | 69% |
When compared to eukaryotic cells, prokaryotic cells are:
less complex |
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more complex |
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similarly complex |
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none of these |
Cells are classified into one of two groups based on whether or not they have a nucleus. Eukaryotic cells have a nucleus, prokaryotic cells do not have a nucleus and therefore have a less complex structure than eukaryotic cells.
A biological community of interacting organisms and their physical environment is known as:
population |
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ecosystem |
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biome |
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community |
An ecosystem is a biological community of interacting organisms and their physical environment. This includes both the biotic (living) and abiotic (non-living).
Which of the following describes the Earth's mantle?
all of these |
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makes up most of Earth's volume |
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dense |
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hot |
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.
Which of these is matter than cannot be separated into different types of matter by ordinary chemical methods?
element |
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compound |
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molecule |
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atom |
An element is matter than cannot be separated into different types of matter by ordinary chemical methods.
What prevents blood pumped out of the ventricles from flowing back into the heart?
capillaries |
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valves |
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platelets |
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atria |
The heart is the organ that drives the circulatory system. In humans, it consists of four chambers with two that collect blood called atria and two that pump blood called ventricles. The heart's valves prevent blood pumped out of the ventricles from flowing back into the heart.