As a construction material, bamboo is as strong as steel and sturdier than concrete. moreover, in tropical areas bamboo is a much less expensive construction material than either steel or concrete and is always readily available. in tropical areas, therefore, building with bamboo makes better economic sense than building with steel or concrete, except where land values are high. which of the following, if true, most to explain the exception noted above? (a) buildings constructed of bamboo are less likely to suffer earthquake damage than are steel and concrete buildings.(b) bamboo is unsuitable as a building material for multistory buildings.(c) in order to protect it from being damaged by termites and beetles, bamboo must be soaked, at some expense, in a preservative.(d) in some tropical areas, bamboo is used to make the scaffolding that is used during large construction projects.(e) bamboo growing in an area where land values are increasing is often cleared to make way for construction.

It is widely assumed that people need to engage in intellectual activities such as solving crossword puzzles or mathematics problems in order to maintain mental sharpness as they age. in fact, however, simply talking to other people—that is, participating in social interaction, which engages many mental and perceptual skills—suffices. evidence to this effect comes from a study showing that the more social contact people report, the better their mental skills. which of the following, if true, most seriously weakens the force of the evidence cited? (a) as people grow older, they are often advised to keep exercising their physical and mental capacities in order to maintain or improve them. (b) many medical conditions and treatments that adversely affect a person's mental sharpness also tend to increase that person's social isolation. (c) many people are proficient both in social interactions and in solving mathematical problems. (d) the study did not itself collect data but analyzed data bearing on the issue from prior studies. (e) the tasks evaluating mental sharpness for which data were compiled by the study were more akin to mathematics problems than to conversation.