Which of the following properties is varying between lanthanoids and actinoids ?

lanthanoids are not radioactive but Actinoids which are a group of 14 elements from Th to Lr are radioactive.

There are 5f electrons in Actinides and 4f electrons in lanthanides. As 5f electrons has less shielding effect than 4f electrons, thereby it donates electrons and becomes more basic.

Actinoids show higher oxidation state because of small gaps between 5f, 6d and 7s subshells.