| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.63 |
| Score | 0% | 73% |
Which of the following is not a characteristic of the Sun?
formed 2.6 billion years ago |
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is composed of hydrogen and helium |
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makes up over 99% of the mass of the solar system |
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is a yellow dwarf star |
The Sun is a G-type main-sequence star (G2V) but is informally known as a yellow dwarf star. Composed of 73% hydrogen and 25% helium, the hot plasma that makes up the Sun reaches 9,900°F (5,505°C) at the surface. It formed approximately 4.6 billion years ago and makes up 99.86% of the mass in the solar system.
Poor balance could indicate an issue with which part of the nervous system?
cerebellum |
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medulla |
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cerebrum |
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spinal cord |
The cerebellum is a large cluster of nerves at the base of the brain that's responsible for balance, movement, and muscle coordination.
Which of these is important for the body's maintenance, growth, and repair?
protein |
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carbohydrates |
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fiber |
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fats |
Found in both animal sources (meat, fish, eggs, cheese) and vegetables (beans, nuts, some grains), proteins are important for the body's maintenance, growth, and repair.
The hottest of Earth's atmospheric layers is which of the following?
troposphere |
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stratosphere |
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thermosphere |
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mesosphere |
Temperatures again increase with altitude in the thermosphere which is the hottest (4,530 °F / 2,500 °C) atmospheric layer due to direct exposure to the Sun's radiation. However, the gas in this layer is highly diluted so even though the atoms of gas may be very high in temperature, there are too few of them to effectively transfer much heat.
Which of these layers is found directly below the Earth's crust?
continents |
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mantle |
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outer core |
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inner core |
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.