Ratio R of molecular abundances (relative to methanol) between low- and normal-metallicity hot-core models for a sample of 96 molecules, shown for three warm-up timescales: 5 × 10⁴ yr (fast), 2 × 10⁵ yr (medium), and 1 × 10⁶ yr (slow). Panels a and b show models with an initial visual extinction of 2 and 3 mag, respectively. Molecules with R lower than one-third at all three timescales are highlighted in red, while those with R higher than three at all three timescales are highlighted in green, and molecules with R within a factor of two of unity (1/2 < R < 2) at all three timescales are highlighted in blue. The other molecules are displayed in black.