*Question*
Q: What can occur during periods of heavy rain? Read this paragraph and choose the correct option from the provided answers: Choices: - volcanoes - glaciers - earthquakes - floods A:
**Answer**
floods

*Question*
Q: What may be lost when waves travel through matter, but not when they travel through space? Read this paragraph and choose the correct option from the provided answers: As you can see in the Figure above , the electric and magnetic fields that make up an electromagnetic wave are perpendicular (at right angles) to each other. Both fields are also perpendicular to the direction that the wave travels. Therefore, an electromagnetic wave is a transverse wave. However, unlike a mechanical transverse wave, which can only travel through matter, an electromagnetic transverse wave can travel through empty space. When waves travel through matter, they lose some energy to the matter as they pass through it. But when waves travel through space, no energy is lost. Therefore, electromagnetic waves don't get weaker as they travel. However, the energy is "diluted" as it travels farther from its source because it spreads out over an ever-larger area. Choices: - matter - frequency - threshold - energy A:
**Answer**
energy

*Question*
Q: What characteristic of reptile eggs allows them to be laid on land instead of in water? Read this paragraph and choose the correct option from the provided answers: Reptile eggs are amniotic, so they can be laid on land instead of in water. Choices: - they are dry - they trap gas - they are circular - they are amniotic A:
**Answer**
they are amniotic

*Question*
Q: Which is the lightest of the widely used structural metals? Read this paragraph and choose the correct option from the provided answers: low, the two metals with the highest ionization energies (beryllium and magnesium) do form compounds that exhibit some covalent characters. Like the alkali metals, the heavier alkaline earth metals impart color to a flame. As in the case of the alkali metals, this is part of the emission spectrum of these elements. Calcium and strontium produce shades of red, whereas barium produces a green color. Magnesium is a silver-white metal that is malleable and ductile at high temperatures. Passivation decreases the reactivity of magnesium metal. Upon exposure to air, a tightly adhering layer of magnesium oxycarbonate forms on the surface of the metal and inhibits further reaction. (The carbonate comes from the reaction of carbon dioxide in the atmosphere. ) Magnesium is the lightest of the widely used structural metals, which is why most magnesium production is for lightweight alloys. Magnesium (shown in Figure 18.6), calcium, strontium, and barium react with water and air. At room temperature, barium shows the most vigorous reaction. The products of the reaction with water are hydrogen and the metal hydroxide. The formation of hydrogen gas indicates that the heavier alkaline earth metals are better reducing agents (more easily oxidized) than is hydrogen. As expected, these metals react with both acids and nonmetals to form ionic compounds. Unlike most salts of the alkali metals, many of the common salts of the alkaline earth metals are insoluble in water because of the high lattice energies of these compounds, containing a divalent metal ion. Choices: - Metal - calcium - potassium - magnesium A:
**Answer**
magnesium