A person is presumed to be alive if it is shown that he was alive within ______ years.

Under Section 108 of the Evidence Act, a person is presumed to be alive if it is shown that they were alive within 30 years. Section 108 creates a presumption of life rather than death - when a person was alive within the 30-year period, the law presumes they continue to be alive. This presumption can of course be rebutted with evidence of death. The 30-year period balances practicality (presuming life after recent contact) with reality (after 30 years, evidence is harder to find).