Statement I ; Actinoids show variable oxidation states

Statement II ; Energy difference between 7s, 6d and 5f subshells is very little

Due to a very small difference in the energies of 7s, 6d and 5f subshells not only 7s and 6d electrons but also 5f electrons involve in bonding in actinoid elements;

$\therefore$they show variable oxidation states;