Symbiogenesis, or endosymbiotic theory, is an evolutionary theory that explains the origin of eukaryotic cells from prokaryotes.It states that several key organelles of eukaryotes originated as a symbiosis between separate single-celled organisms.he theory of symbiogenesis (Greek: ÏÏÎ½ syn together, Î²Î¯ÏÏÎ¹Ï biosis living, and Î³Î­Î½ÎµÏÎ¹Ï genesis origin or birth) theory were first articulated by the Russian botanist Konstantin Mereschowsky in 1910, although he described the fundamental elements of the theory were described in a paper five years earlier.
Definition of rider: Additional clause, document, or slip of paper that adds, alters, amends, or removes the provisions of an associated or attached agreement or contract (such as an insurance policy) or a negotiable ...
Rider (exclusionary rider) A rider is an amendment to an insurance policy. Some riders will add coverage (for example, if you buy a maternity rider to add coverage for pregnancy to your policy). In most states today, an exclusionary rider is an amendment permitted in individual health insurance policies that permanently excludes coverage for a health condition, body part, or body system. Starting in September 2010, under the Affordable Care Act, exclusionary riders cannot be applied to coverage for children.