**The most important metric is `petal_length`.** The highest and lowest petal_length records are a virginica at 6.9 and a setosa at 1.0. I picked it because it separates the three species best. Nothing in the data marks a metric as "important", so this is a judgement based on the species breakdown. **Why petal_length** - The species averages are far apart: setosa 1.46, versicolor 4.26, virginica 5.55 (the gold table `iris_by_species`). - Setosa's maximum (1.9) is well below versicolor's minimum (3.0), so setosa is fully separable. - Versicolor (maximum 5.1) and virginica (minimum 4.5) overlap only slightly. - Sepal width separates the species poorly. Its ranges overlap heavily: versicolor runs 2.0–3.4, virginica 2.2–3.8 and setosa 2.3–4.4. - petal_width also separates the species well (averages 0.25, 1.33 and 2.03), so it is a close second. I picked petal_length because it has the widest spread between species averages. **Highest and lowest records by petal_length** (the extremes query result) - **Highest:** a *virginica* specimen with petal_length 6.9, petal_width 2.3, sepal_length 7.7 and sepal_width 2.6. - **Lowest:** a *setosa* specimen with petal_length 1.0, petal_width 0.2, sepal_length 4.6 and sepal_width 3.6. Both extremes come from different species, which fits petal_length being the main separator. The query returned one record per extreme, and these values may be shared by other specimens. The 1.0 minimum in particular could be tied within setosa, so the lowest record shown may be one of several.