Select all the discoveries that scientists have made by doing research with the slime mold Dictyostelium discoideum from the choices below.
1) the protein myosin is required for cytokinesis
2) lipids are involved in spore formation
3) actin and myosin proteins can produce cell movement
4) gap junctions between cells will promote cell aggregation
5) certain chemicals signal cell differentiation
6) chemotaxis involves special membrane proteins