Trait B is likely to have arisen earlier. This is because the organism is asexually reproducing and therefore the number of organism having a particular trait depends on the duration of time since the trait has been acquired.
We cannot really say which of the organisms have a better body design. Each of these organism have a body design which help them to survive in their environment. Chimpanzee has the most complex body design, but even they, cannot survive in highly extreme environments like bacteria can, which possess the simplest body design of the 4.
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