The plesiosaur flipper is convergent with other flipper forms becuase even though they don't share the same evolutionary path, in other words, they don't have a common ancestor with flippers, different animals reached to a simmilar structure with the same function that is locomotion in water.
Around 4.1 billion years ago the first single celled organism appeared
Plant a rain garden,practice no till farming,practice contour farming. all of these are options
