Complex sentence: The shape of the jangada incorporates some interesting advances of neolithic handcraft-improved materials were found and the phenomenons were better observed, in "research projects", and these details are kept guarded in the memory of artisans.
Split into simpler sentences: The shape of the jangada incorporates some interesting advances of neolithic handcraft-improved materials were found and the phenomena were better observed in "research projects". The details are kept guarded in the memory of artisans.