Answer the following question given this paragraph: Phosphorus The name phosphorus comes from the Greek words meaning light bringing. When phosphorus was first isolated, scientists noted that it glowed in the dark and burned when exposed to air. Phosphorus is the only member of its group that does not occur in the uncombined state in nature; it exists in many allotropic forms. We will consider two of those forms: white phosphorus and red phosphorus. White phosphorus is a white, waxy solid that melts at 44.2 C and boils at 280 C. It is insoluble in water (in which it is storedsee Figure 18.24), is very soluble in carbon disulfide, and bursts into flame in air. As a solid, as a liquid, as a gas, and in solution, white phosphorus exists as P4 molecules with four phosphorus atoms at the corners of a regular tetrahedron, as illustrated in Figure 18.24. Each phosphorus atom covalently bonds to the other three atoms in the molecule by single covalent bonds. White phosphorus is the most reactive allotrope and is very toxic. Q: When what element - whose name means "light bringing" - was first isolated, scientists noted that it glowed in the dark and burned when exposed to air? Choices: - oxygen - mercury - neon - phosphorus A:
phosphorus
Answer the following question given this paragraph: Tectonic plates are large segments of the Earth's crust that move slowly. Suppose that one such plate has an average speed of 4.0 cm/year. (a) What distance does it move in 1 s at this speed? (b) What is its speed in kilometers per million years? 10. (a) Refer to Table 1.3 to determine the average distance between the Earth and the Sun. Then calculate the average speed of the Earth in its orbit in kilometers per second. (b) What is this in meters per second?. Q: What are the large segments of the earth's crust that ordinarily move very slowly? Choices: - ocean plates - lava plates - distinct plates - tectonic plates A:
tectonic plates
Q: Answer the following question given this paragraph: Q: What ensures that seeds germinate only when conditions for seedling survival are optimal? Choices: - germination dormancy - seed forcing - survival dormancy - seed dormancy A:
A: seed dormancy
Question: Answer the following question given this paragraph: Q: Of all the mineral nutrients, what contributes the most to plant growth and crop yields? Choices: - oxygen - methane - silicon - nitrogen A:
Answer: nitrogen
*Question*
Answer the following question given this paragraph: Over time, deposited sediments may harden into rock. First, the sediments are compacted . That is, they are squeezed together by the weight of sediments on top of them. Next, the sediments are cemented together. Minerals fill in the spaces between the loose sediment particles. These cementing minerals come from the water that moves through the sediments. Sedimentary rocks that form from sediments are called "clastic rocks. " Clastic rocks are rock fragments that are compacted and cemented together ( Figure below ). Q: Over time, deposited sediments may harden into what? Choices: - coral - fossils - deltas - rocks A:
**Answer**
rocks
Answer the following question given this paragraph: Q: Corals build hard exoskeletons that grow to become what? Choices: - algae - stability reefs - fungi - coral reefs A:
coral reefs