Explanation: In a way this thinai classification is said to reflect the uneven socio-economic developments of the different localities. That is seen in the political forms too.

• Three levels of rulers are found:1) Kizhar, 2) Velir, 3) Vendar.
• Kizhar were the heads of the villages or a small territory, later known as nadu. They were the chiefs of tribal communities living in specific areas.
• The Vendar were kings controlling larger, fertile territories.
• The Velir, who were many in number, controlled the territories of varied geographical nature, mainly hilly and forest areas, that were in between the muvendar’s fertile territories.

Source: Tamil Nadu NCERT