Final answer:
Members of the new council created by Cleisthenes to assist the Athenian assembly were chosen by lot, which facilitated equal participation and helped establish a more democratic system.
Step-by-step explanation:
Cleisthenes, an influential Athenian leader, created a new council to assist the assembly in its duties during his governance after 508 BCE. This new council, which played a crucial role in the functioning of Athenian democracy, was composed of members chosen by lot. This method of selection was intended to give all male citizens, including the poor who were previously excluded due to their inability to afford weapons and serve as hoplites, an equal chance at participating in governance. Cleisthenes' reforms, including the creation of new tribes that mixed men of different backgrounds and the establishment of the Council of Five Hundred, helped to unite the Athenian community and led to a more democratic society. This system ensured the representation of Athenians from the entire region of Attica and prevented the concentration of power within a small elite.