| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.48 |
| Score | 0% | 70% |
Which of these parts of digestion takes place in the mouth?
breaking down fats |
|
absorbing nutrients |
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breaking down starches |
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breaking down proteins |
Digestion begins in the mouth where the teeth and tongue break down food mechanically through chewing and saliva, via the enzyme salivary amylase, starts to break starches down chemically. From the mouth, food travels down the esophagus where contractions push the food into the stomach.
An element in the physical state of __________ maintains a constant volume and shape.
gel |
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gas |
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solid |
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liquid |
An element in a solid state has atoms or molecules that are constricted and do not move freely. Solids maintain a constant volume and shape and exist at a lower temperature than liquids or gases.
The Sun is a __________-type main-sequence star.
S |
|
G |
|
E |
|
D |
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.
Which of the following is the smallest component of an element that still retains the properties of the element?
molecule |
|
atom |
|
neutron |
|
element |
An atom is the smallest component of an element that still retains the properties of the element.
The asteroids in the Kuiper belt are composed of which of the following?
gaseous methane, ammonia, and water |
|
rock |
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minerals |
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frozen methane, ammonia, and water |
The Kuiper Belt is similar to the asteroid belt but much larger. Extending beyond the orbit of Neptune, it contains objects composed mostly of frozen methane, ammonia, and water. Most notably, the Kuiper Belt is home to Pluto, a dwarf planet that, until a 2006 reclassification, was considered the ninth planet of the solar system.