Summary: During cytokinesis. a contractile ring consisting of unbranched filamentous actin (F-actin) and myosin II constricts at the cell equator. Unbranched F-actin is generated by formin. and without formin no cleavage furrow forms. https://www.jmannino.com/best-catch-Sophie-Allport-Bee-Blackout-Ready-Made-Eyelet-Curtains-Duck-Egg-special-save/