In humans, ingested protein is broken down into amino acids, all of which must compete to enter the brain. Subsequent ingestion of sugars leads to the production of insulin, a hormone that breaks down the sugars and also rids the bloodstream of residual amino acids, except for tryptophan. Tryptophan then slips into the brain uncontested and is transformed into the chemical serotonin, increasing the brain’s serotonin level. Thus sugars
cause mood elevation, helping one to feel relaxed and anxiety-free.
Which one of the following is an assumption on which the argument depends?
(A) Elevation of mood and freedom from anxiety require increasing the level of serotonin the brain.
(B) Failure to consume foods rich in sugars results in anxiety and a lowering of mood.
(C) Serotonin can be produced naturally only if tryptophan is presented in the bloodstream.
(D) Increasing the level of serotonin in the brain promotes relaxation and freedom from anxiety.
(E) The consumption of protein-rich foods results in anxiety and a lowering of mood.
For this Q can all A,B & D be correct answers?
CR bible says when we have causal reasoning as in this modified Q, effect(mood elevation) occurs only when cause(sugar) occurs.
And in such Qs assumption question is similar to strengthen question for which correct answer fits
"cause doesn't occur, effect doesn't occur" category.
I am changing B(which originally is like "no cause, OPPOSITE effect" to
B) Mood elevation is not observed in people who consume foods not rich sugar. Now it is "no cause, no effect". Does that mean this is also a correct answer?
Also according to CR bible, since this causal reasoning Q, sugar is the
only reason for mood elevation.
That means even A should answer the Q.
What do you think?
Below is original Q with straightforwad answer
Quote:
In humans, ingested protein is broken down into amino acids, all of which must compete to enter the brain. Subsequent ingestion of sugars leads to the production of insulin, a hormone that breaks down the sugars and also rids the bloodstream of residual amino acids, except for tryptophan. Tryptophan then slips into the brain uncontested and is transformed into the chemical serotonin, increasing the brain’s serotonin level. Thus, sugars can play a major role in mood elevation, helping one to feel relaxed and anxiety-free.
Which one of the following is an assumption on which the argument depends?
(A) Elevation of mood and freedom from anxiety require increasing the level of serotonin in the brain.
(B) Failure to consume foods rich in sugars results in anxiety and a lowering of mood.
(C) Serotonin can be produced naturally only if tryptophan is present in the bloodstream.
(D) Increasing the level of serotonin in the brain promotes relaxation and freedom from anxiety.
(E) The consumption of protein-rich foods results in anxiety and a lowering of mood.