Answer the following question given this paragraph: Q: What cannot exist between energy levels? Choices: - crystals - protons - cells - electrons A:
electrons
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Answer the following question given this paragraph: Hybridization involves only bonds, lone pairs of electrons, and single unpaired electrons (radicals). Structures that account for these features describe the correct hybridization of the atoms. However, many structures also include resonance forms. Remember that resonance forms occur when various arrangements of bonds are possible. Since the arrangement of bonds involves only the unhybridized orbitals, resonance does not influence the assignment of hybridization. For example, molecule benzene has two resonance forms (Figure 8.26). We can use either of these forms to determine that each of the carbon atoms is bonded to three other atoms with no lone pairs, so the correct hybridization is sp2. The electrons in the unhybridized p orbitals form bonds. Neither resonance structure completely describes the electrons in the bonds. They are not located in one position or the other, but in reality are delocalized throughout the ring. Valence bond theory does not easily address delocalization. Bonding in molecules with resonance forms is better described by molecular orbital theory. (See the next module. Q: Bonding in molecules with resonance forms is better described by which theory? Choices: - Geiger theory - string theory - Pascal's theory - molecular orbital theory A:
molecular orbital theory
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Answer the following question given this paragraph: Bottleneck effect occurs when a population suddenly gets much smaller. This might happen because of a natural disaster such as a forest fire. By chance, allele frequencies of the survivors may be different from those of the original population. Q: What effect occurs when a population suddenly gets much smaller, due to natural disaster or other cause? Choices: - convergence effect - limitation effect - extinction effect - bottleneck effect A:
bottleneck effect
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Answer the following question given this paragraph: Keeping the rate of metabolism high takes a constant and plentiful supply of oxygen. That's because cellular respiration, which produces energy, requires oxygen. The lungs and heart of mammals are adapted to meet their oxygen needs. Q: A constant and plentiful supply of oxygen is required in order to maintain a high rate of what? Choices: - digestion - cell division - magnesium - metabolism A:
metabolism
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