التعريف: A piece of rock with a grain size above 300 millimetres in diameter. Smaller boulders are, at times, referred to as rocks or stones. [ https://en.wikipedia.org/wiki/Boulder]
التعريف: Capable of creating a new organism by combining the genetic material of two gametes, which may come from two parent organisms or from a single organism, in the case of self-fertilizing hermaphrodites.
