Time evolution of Q(He II)/Q(H I) for non-rotating (top panel) and rotating stars with v/v_crit = 0.4 (bottom panel) for three metallicities, [Fe/H]=0.0 (blue solid line), −1.0 (orange dashed), −2.0 (green dotted), and for highly clumped winds. The blue band shows the approximate range of Q(He II)/Q(H I) ∼ 0.0021 − 0.0371 expected to produce line intensity ratios I(He IIλ4686)/I(Hβ) in the range observed in spatially resolved observations of the Cartwheel Galaxy (Mayya et al. 2023), ≈0.004 − 0.07.