It is the unit everything else is built from: rates, comparisons, variability. Twelve questions on two platforms are twenty-four observations.
Each one keeps the exact question and its version, the platform, the date and time, the complete answer, the brands in order, the sources shown and a status: valid, error or unavailable. Errors are not deleted: they are counted apart.
A screenshot is not an observation. It shows that someone saw something, not with which exact question or what was below the crop.