#19 - People should avoid taking the antacid calcium

[gweatherall]

I'm hoping that someone might be able to help with the difference between answer choices C and D on this one. I chose C because it seemed to me that that the prompt suggested that taking less than half a gram could neutralize stomach acids, but more than half a gram would lead to secretion of more stomach acids.

I rejected D because it seemed like both a contradiction and too strong a claim.

Where did I go wrong here? Thanks in advance, all!

[Luke Haqq]

Hi gweatherall!

Answer (D) states, "Half a gram of calcium carbonate can causally contribute to both the secretion and the neutralization of stomach acids." The language I italicized makes that answer choice rather weak, as opposed to being too strong. That is, it's not claiming that calcium carbonate always does causally contribute in that way.

Further, we know (D) must be the case because the stimulus states, "just half a gram of [calcium carbonate] can stimulate the production of gastrin, a stomach hormone that triggers acid secretion." That gets us the fact that it can causally contributes to acid secretion. And in the second sentence, we're told the fact that half a gram of calcium carbonate has the capacity to neutralize acids ("...for despite its capacity to neutralize stomach acids..."). Thus we know the second part of (D), which is why is must be true based on the information given.

We can't know (C) is true because the information given doesn't tell us any facts about what is or is not the case if one takes less than half a gram. The stimulus only focuses on half a gram or more of calcium carbonate.

[gweatherall]

Ah, I see my problem here- I was neglecting to consider the idea of an actual half of a gram, or an exact half, in other words- and saw the idea of avoiding "more than half a gram" to mean that one should take *less* than half a gram. A good reminder to be careful of sizes of proportions! Thanks, Luke!