Mass-independent isotopic data for Earth, Mars, and NC meteorite parent bodies. The ε⁵⁴Cr data are reversely plotted for ease of comparison with the ∆¹⁷O data and simulation results. The blue triangles are the ε⁵⁴Cr and ∆¹⁷O data for the NC meteorite parent bodies, shown as the cumulative distribution of these data with the y axis representing the cumulative fraction. The blue-shaded areas are the kernel density estimates of these data with the y axis representing the probability density. The green and brown bands represent the ε⁵⁴Cr and ∆¹⁷ O values for Earth and Mars with uncertainties, respectively. The isotopic data are from the literature (Table A.1).