The actor's letters form the 'basis' of the biography. [=the biography is based on the actor's letters; the most important information in the biography comes from the actor's letters]
This principle forms the 'basis' [='base', 'foundation'] of the country's economic policies and will provide a firm 'basis' for future development.
These stories have very little 'basis' [='foundation'] in fact/reality. [=these stories are not based on or supported by facts/reality]
(..) I have a three-page phone list with every one of our enemies calling to deny responsibility for the attack. Cochrane: All US military bases are on full alert, and the USS Eisenhower is currently hard charging towards the Fifth Fleet stationed in the Persian Gulf. I understand alerting our bases, (..)2016 TvShow: Designated Survivor Title: Pilot Season: 1 Episode 1