<P> Tissues can change their shape and separate into distinct layers via cell contractility . Just as in muscle cells, myosin can contract different parts of the cytoplasm to change its shape or structure . Myosin - driven contractility in embryonic tissue morphogenesis is seen during the separation of germ layers in the model organisms Caenorhabditis elegans, Drosophila and zebrafish . There are often periodic pulses of contraction in embryonic morphogenesis . A model called the cell state splitter involves alternating cell contraction and expansion, initiated by a bistable organelle at the apical end of each cell . The organelle consists of microtubules and microfilaments in mechanical opposition . It responds to local mechanical perturbations caused by morphogenetic movements . These then trigger traveling embryonic differentiation waves of contraction or expansion over presumptive tissues that determine cell type and is followed by cell differentiation . The cell state splitter was first proposed to explain neural plate morphogenesis during gastrulation of the axolotl and the model was later generalized to all of morphogenesis . </P> <P> Cancer can result from disruption of normal morphogenesis, including both tumor formation and tumor metastasis . Mitochondrial dysfunction can result in increased cancer risk due to disturbed morphogen signaling . </P>

Which statement best describes an element of the developmental pathways model