The Law of Segregation states that every individual possesses a pair of alleles (assuming diploidy) for any particular trait and that each parent passes a randomly selected copy (allele) of only one of these to its offspring.

Application of Mendel's First Law
Application of Mendel's First Law, Education Portal Adademy, Video and quiz.
http://education-portal.com/academy/lesson/applica...
Mendel's First Law: The Law of Segregation
Mendel's First Law: The Law of Segregation, Education Portal Academy, Video and quiz.
http://education-portal.com/academy/lesson/mendels...
Principle of Segregation
Principle of Segregation, Scitable, By Nature Education, Has a good definition of the principle plus links to further information.
http://www.nature.com/scitable/definition/principl...