1. The Bible clearly speaks of God the Son, God the Father, and God the Holy Spirit. But emphasizes that there is only ONE God. The Trinity is a way of acknowledging what the Bible reveals to us about God is the Father, Son, and the Holy Spirit. That God is three "Persons" but all exist within one essence. In other religions we also see one Supreme Being, being created into other gods/goddess and given certain strengths or is the reason for a creation. Within Christianity all powers or strengths and creation comes from one source; God, because of this I believe that Christianity is still considered a monotheistic religion.
2. The Protestant Reformation was a major 16th century European movement aimed initially at reforming the beliefs and practices of the Roman Catholic Church.
3. Some of the differences between the Eastern Orthodoxy, Roman Catholicism, and Protestantism are that within authority and traditions; the Roman Catholic church believes in authority regarding theological truth as deriving from three sources; the Pope and Bishops, the traditions of the Church and Scripture itself. The Eastern Orthodox recognizes Church Tradition and Scripture, while Protestant denominations recognize only the authority of Scripture.
4. Fundamentalists interpret the Bible as the literal word of God. They rejected some new scientific and geology findings, but dismissed or reinterpret other findings to fit the bible. For example, most fundamentalists believe that the world was made in seven 24hr day as told in Genesis. However, social gospel groups take the biblical teachings and try to apply them to life situations. As the 20th century approached social gospel beliefs and ideals became more renowned due to rapid globalization and industrialization.