Panel (a): carbon isotope ratios of ¹²C/¹³C as a function of the effective temperature for the 1.3 M_⊙ solar metallicity stars with different initial rotational velocities. Panel (b): for the ratios of ¹⁴N/¹²C. Panel (c): for the ³He. The model with the thermohaline mixing (solid lines) and without the thermohaline mixing (dashed lines) are indicated in three panels. The observational samples are from these references (Tautvaišienė et al. 2010, 2013; Mikolaitis et al. 2012; de La Reza et al. 2003; McCormick et al. 2023).