You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "who came up with the theory of endosymbiosis?" whose answer is Konstantin Mereschkowski.
Each document should contain about 30 words, and these documents should contain useful information.

Query: who proposed the theory of endosymbiosis
Useful Output:

Doc 1: In 1905, the Russian botanist Konstantin Mereschkowski first proposed symbiogenesis, or endosymbiotic theory. This theory states that
Doc 2: Origin of Eukaryotic Cells (Margulis 1970) by Lynn Margulis (1938–2011) is a famous book that explained the endosymbiotic theory in detail from
Doc 3: The endosymbiotic theory states that mitochondria and chlopoplasts in today's eukaryotic cells were once separate prokaryotic microbes.
Doc 4: Serial Endosymbiosis Theory, or SET, was conceived and developed by Lynn Margulis, to explain the greatest discontinuity in the history of
Doc 5: Fifty years ago, Lynn Margulis proposed a comprehensive hypothesis on the origin of eukaryotic cells with an emphasis on the origin of