Complex sentence: The cells of the embryo break down within hours of their death, under the effect of its own enzymes; bacteria invade the dacaying embryo before its cells can collapse, and biofilms taking on and preserving the three dimensional structure of the cells.
Split into simpler sentences: The cells of the embryo break down within hours of their death, under the effect of its own enzymes. Bacteria invade the decaying embryo before its cells can collapse, and biofilms take on and preserve the three dimensional structure of the cells.