Q: What are modified leaves that bear sporangia? Read this paragraph and choose the correct option from the provided answers: Choices: - spines - neutrophils - sporozoans - sporophylls A:
sporophylls

Q: Radiation can be absorbed or shielded by materials, particularly what material used to make protective aprons worn by x-ray administrators? Read this paragraph and choose the correct option from the provided answers: Radiation can be absorbed or shielded by materials, such as the lead aprons dentists drape on us when taking x rays. Lead is a particularly effective shield compared with other materials, such as plastic or air. How does the range of radiation depend on material? Ionizing radiation interacts best with charged particles in a material. Since electrons have small masses, they most readily absorb the energy of the radiation in collisions. The greater the density of a material and, in particular, the greater the density of electrons within a material, the smaller the range of radiation. Collisions Conservation of energy and momentum often results in energy transfer to a less massive object in a collision. This was discussed in detail in Work, Energy, and Energy Resources, for example. Different types of radiation have different ranges when compared at the same energy and in the same material. Alphas have the shortest range, betas penetrate farther, and gammas have the greatest range. This is directly related to charge and speed of the particle or type of radiation. At a given energy, each , , or will produce the same number of ionizations in a material (each ionization requires a certain amount of energy on average). The more readily the particle produces ionization, the more quickly it will lose its energy. The effect of charge is as follows: The has a charge of +2q e , the has a charge of q e , and the . Choices: - cotton - steel - carbon - lead A:
lead

Q: What is the sequence of elementary steps that together comprise an entire chemical reaction called? Read this paragraph and choose the correct option from the provided answers: The overall balanced equation for a chemical reaction does not always tell us how a reaction actually proceeds. In many cases, the overall reaction takes place in a series of small steps. An elementary step (or elementary reaction) is one step in a series of simple reactions that show the progress of a reaction at the molecular level. In terms of collision theory, each elementary step corresponds to a single collision. A reaction mechanism is the sequence of elementary steps that together comprise an entire chemical reaction. As an analogy, consider the route that you might take while driving to the grocery store. That route may consist of several turns, similar to the elementary steps. The overall reaction specifies only the beginning point (your house) and the final destination (the store), with no information about the specifics in between. Choices: - reaction circle - mechanical mechanism - basic reaction - reaction mechanism A:
reaction mechanism

Q: What forms when nitrogen and oxygen combine at high temperatures? Read this paragraph and choose the correct option from the provided answers: Nitrogen oxides form when nitrogen and oxygen combine at high temperatures. This occurs in hot exhausts from vehicles, factories, and power plants. Choices: - oxygen oxide - ammonia oxide - carbon dioxide - nitrogen oxide A:
nitrogen oxide