SAT #16 Reading (Question 51)

Question

Based on data in the figure, which choice is a reasonable conclusion about lunar glass bead green #5?

Answer 1

Answer Choice C is the correct answer because at the core of the bead the water concentration is at about 30 parts per million, while at 120 micrometers from the core the water concentration is at about 15 parts per million. This means that the water concentration is about half that at the core at 120 micrometers, which most closely matches Answer Choice C which says of the glass bead that “its water concentration at 120 micrometers is approximately half that at its core.” Answer Choice A is incorrect because the figure does show water detectable beyond 100 micrometers from the core, at both 110 and 120. Answer Choice B is incorrect because it makes too strong a claim for the figure to measure, and because these values may have fluctuated over time. Answer choice D is incorrect because the figure doesn’t show us how the glass bead varied in its water concentration over time, so we can’t say how much it has declined.