Impact of rotation on the HRD and several surface abundances normalised to their initial values. Models with a mass of 1.5 M_⊙ are shown in the top row (panels a-e), and models with a mass of 6 M_⊙ are shown in the second row (panels f-j). Different initial rotation rates are shown by different colours. The first column shows the HRD of the selected models. The second and third columns show the C-isotope ratio and the C/N ratio, respectively, with respect to the initial values. That is, we plot the quantity (X/Y)−(X/Y)_ini, where X/Y = n_X/n_Y is number density ratio of species X and Y, and the (X/Y)_ini value is specified in the plot. The abundances of ¹⁶O and ⁷Li are shown in the fourth and fifth columns, respectively. In the latter cases, we plot the quantity A(X)−A(X)_ini, where A(X) = log(n_X/n_H)+12 is the abundance of element X, and A(X)_ini is its initial value, as specified in each panel. n_H is the hydrogen density number. The models are shown from the ZAMS to the RGB tip for the 1.5 M_⊙ model, and at the end of the He-burning phase for the 6 M_⊙. The black dot marks the TAMS.