| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.13 |
| Score | 0% | 63% |
When two air masses meet and neither is displaced, what kind of front is present?
occluded |
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warm |
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stationary |
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cold |
When two air masses meet and neither is displaced, a stationary front is created. Stationary fronts often cause persistent cloudy wet weather.
The two heart chambers that pump blood called:
valves |
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aorta |
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atria |
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ventricles |
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.
Which of the following is true about species groups?
a biome is a made up of a group of biospheres |
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an ecosystem is a biological population |
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a community is made up of a group of populations |
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a population is made up of a group of communities |
A population is a group of organisms of the same species who live in the same area at the same time. A community is a group of populations living and interacting with each other in an area.
Arteries carry __________ blood at __________ pressure.
oxygenated, low |
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oxygenated, high |
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deoxygenated, low |
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deoxygenated, high |
Veins carry blood back to the heart from the body. While arteries are thick-walled because they carry oxygenated blood at high pressure, veins are comparatively thin-walled as they carry low-pressure deoxygenated blood. Like the heart, veins contain valves to prevent blood backflow.
Blood is created in:
bone marrow |
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red blood cells |
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the liver |
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the heart |
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.