Variation of flux ratios, F_CO2/F_C2H2 and F_¹³CO2/F_¹³CCH2, across different SFRs or moving groups. We include Sz114 (Xie et al. 2023). The dashed line indicates a line with slope of unity. Due to the non-detections of both ¹³CO₂ and ¹³CCH₂ in J0438, we present it with a vertical dotted line. The colors indicate the different SFRs or the moving groups shown in the legend at the top. The ages indicated are canonical values commonly used in the literature; however, recent studies indicate a larger diversity in the ages of sources within each SFR (e.g., Ratzenböck et al. 2023).