| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.24 |
| Score | 0% | 65% |
Changes to an object's speed or direction of motion are caused by which of the following?
work |
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a force |
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power |
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kinetic energy |
Force is applied to change an object's speed or direction of motion.
Earth's history is divided into time periods, which of these is the longest time period?
epoch |
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era |
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age |
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eon |
The Earth is approximately 4.6 billion years old and its history is divided into time periods based on the events that took place and the forms of life that were dominant during those periods. The largest graduation of time is the eon and each eon is subdivided into eras, eras into periods, periods into epochs, and epochs into ages.
A major difference between sound waves and light waves is which of the following?
a sound wave is mechanical while a light wave is electromagnetic |
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a sound wave is much slower than a light wave |
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all of these are correct |
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a sound wave cannot travel through a vacuum |
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.
In the heart, blood flows from the __________ ventricle to the lungs then back to the heart via the __________ atrium.
left, left |
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right, left |
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right, right |
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left, right |
The two largest veins in the body, the venae cavae, pass blood to the right ventricle which pumps the blood to the lungs through the pulmonary artery. Blood picks up oxygen in the lungs and returns it to the left atrium via the pulmonary vein.
Examples of secondary consumers include:
wolves |
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chickens |
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plankton |
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grasshoppers |
Secondary consumers (carnivores) subsist mainly on primary consumers. Omnivores are secondary consumers that also eat producers. Examples are rats, fish, and chickens.