<span>Lynn Margulis supported the endosymbiotic theory and
studied mitosis in cells. She was an American evolutionary theorist who made
great significance in the symbiosis of organisms in biological evolution. She
is also a developer of the Gaia Theory, which believes that the Earth functions
as a single self-regulating system. </span>
Yes, like on land humans are at the top of the food chain and the rest of the animals on land trickles down from there. Yet the only difference with a marine food chain is instead of land animals and humans the food chain consists of fish,sharks, and other water dwelling animals.
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There environment that get there food from wherever that can find it