Alter Boys are young males typically 8 to 12 years of age who assist the priest during the Mass ceremony. They escort the priest onto the the altar platform and also when he leaves. They ring bells and get the vessels of water and wine that the priest pours into his chalice. Sometimes they carry a cross at a procession in the church.
A Deacon is a congregational member that wants to be close to the priest and help out during religious ceremonies. He feels he is very pious and gets great satisfaction being a part of the Mass ceremony. They help by leading the congregation in prayers and chants.
Monks in Jerusalem
Orthodox monastics separate themselves from the world in order to pray unceasingly for the world. They do not, in general, have as their primary purpose the running of social services, but instead are concerned with attaining theosis, or union with God.
Only men are allowed to be Priests (and no transgenders allowed). They take a vow of celibacy. A priest participates in priesthood after the Sacrament of Holy Orders, he acts in persona Christi Capitis, representing the person of Christ. Only Priests can perform the ceremony of the Eucharist, which derives from the story of the Last Supper,
As of December 31, 2014, there were 415,792 Catholic priests worldwide, decreased 5,000 since 1970. The worldwide Catholic population has nearly doubled, growing from 653.6 million in 1970 to 1.229 billion in 2012.
Monsignor is a honorific title that is requested by a bishop to the pope and given to a priest. It is given for dedicated valuable service or holds a special position of governance by a priest.
In March 2013, Pope Francis suspended the granting of the honorific title of Monsignor except to members of the Holy See's diplomatic service.
This is simply an ordained priest that has been given authority to oversee the flock. This authority is typically a geographic area called a diocese.
There are different levels of bishops. A Metropolitan bishop is in charge of a group of diocese. The Archbishop is in charge of a major metropolitan area and is more of an honorary title or importance.
The Pope is Pontifex Maximus (greatest priest), Bishop of Rome, Leader of the worldwide Catholic Church, and the head of state of Vatican City (city-state) a recognized country withing the city of Rome.