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Convergent evolution of helicoidal structures in animals and plants (kingdoms Animalia and Plantae, respectively). Chitin nanofibrils in the exoskeleton (cuticle) of insects and cellulose microfibrils in the epidermal wall(s) of plants display the same kind of architecture (design), which is largely the result of directed molecular self-assembly. Primary serial endosymbiosis was a key event in the history of life that gave rise to the evolution of multicellular organisms.
