Database Management System - Old Questions

How participation constraints are used in ER diagram? Explain. Also Construct an E-R diagram for a car insurance company whose customer own one or more cars each.Each car  has associated with it zero to any number of recorded accidents. Each insurance policy covers one or more cars and has one or more premium payments associated with it. Each payment is for a particular period and has an associated due date, and the date when the payment was received.