A medical researcher hypothesizes that a particular gut bacterium plays a causal role in regulating mood by producing neurotransmitter precursors that reach the brain, rather than merely correlating with mood.
Which finding, if true, would most strongly support the researcher's hypothesis?
- Acheck_circle
Mice given the bacterium showed reduced anxiety-like behavior compared to genetically identical mice without the bacterium, with elevated levels of relevant neurotransmitter precursors in their blood.
- B
The bacterium is more common in some populations than others.
- C
Some other bacteria also live in the human gut.
- D
People with low levels of the bacterium often report low mood.
Explanation
A is an interventional comparison with a measured mechanism, supporting causation. B is correlational; C and D are tangential.