Why is there a "urine test" and "stool inspection", but there is no "fart inspection"?

appendix:

1. Teach you the two good ways of farting sounds. The first is to adjust the posture immediately when you plan to fart, and push your buttocks to let the hips naturally separate and open a passage for the fart.The second is that in the process of fart, keep the butt muscles nervous, resulting in the effect of chrysanthemum tightness, which can also greatly reduce the fart, and the pro -test is effective.

2. Dr. Karl's fart testing experiment actually has a control group. One person takes off his pants and farts, one person wears pants and farts. Finally, the petri dish where the pants are farted.Bacterial.

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