# Circadian phenomena -- internal 24-hour clock mechanisms of humans and other living beings -- defy material explanation. Examples include how some people are unable to change the timing of their need for sleep for each day, and how plants exhibit clock-like behavior regardless of their exposure to sunlight. In addition, there is a weekly clock cycle for many phenomena, which has a clear biblical basis but defies any materialistic explanation.<ref>http://www.biblestudy.org/godsrest/mysterious-seven-day-cycle-in-plants-animals-man-2.html</ref> | # Circadian phenomena -- internal 24-hour clock mechanisms of humans and other living beings -- defy material explanation. Examples include how some people are unable to change the timing of their need for sleep for each day, and how plants exhibit clock-like behavior regardless of their exposure to sunlight. In addition, there is a weekly clock cycle for many phenomena, which has a clear biblical basis but defies any materialistic explanation.<ref>http://www.biblestudy.org/godsrest/mysterious-seven-day-cycle-in-plants-animals-man-2.html</ref> |