Please explain the process in which the priest/bishop picks the Holy Bread for the Holy Communion and its symbolism/significance.
The most senior clergy celebrating the Divine Liturgy chooses from either 3, 5, or 7 circle shaped leavened bread. The number must be uneven, as there is no one equal to Christ. Leaven is symbolic of sin that dies in the fire (i.e., the oven), as when Christ carried our sins on the cross and died for us. The priest stands at the threshold of the sanctuary, faces the congregation with his back to the altar, and crosses his hands in the symbol of the cross. The priest chooses the Bread (i.e., the Lamb without blemish—the offering of the Passover Lamb).