Abundance ratios of five SMSs with contributions by the galactic stars for the case of 10% mass loss. The green, yellow, and brown stars indicate ratios for GS 3073, CEERS 1019, and GN-z11, respectively. If the chemically mature stellar population contributes C, N, O, and Ne mass fractions χ_C = 2.8 × 10⁻⁴, χ_N = 8 × 10⁻⁵, χ_O = 1.2 × 10⁻³, and χ_Ne = 9.4 × 10⁻⁴ then all 10 models can reproduce the observed near-vertical transition in the N/O ratio while also explaining the C/O ratios (X. Ji et al. 2024).