EXPLANATION QUESTION #1


B and C

Choice (A) is incorrect because the passage says that guttation occurs only in vascular plants, and there is no discussion of the difference in the number of vascular plants that exist in the two climates mentioned. Choice (B) is supported because the text says that dew results from a change between surface and atmospheric temperatures. Therefore, an analysis that does not factor in those measurements would be inadequate, as this answer indicates. The described analysis is also inadequate because the passage provides no information on which process is more likely to occur, given that the conditions for both exist. Choice (C) is supported because the passage says that guttation begins when water moves from saturated soil. In an arid climate, the soil is not likely to be saturated with moisture. The phrase under natural conditions in (C) should eliminate exceptions, such as irrigation systems, when considering this choice.