Peter and John

Who were "uneducated" and "untrained" (Acts 4:13)?
"Peter and John" (Acts 4:13).

So what right did Peter and John have to challenge the most educated and the best trained religious leaders in their nation?
They had been with Jesus, who had taught and gifted them, including with a sign of His power that the religious leaders could not deny (see lame man).

Who appoints and gifts people to teach about God?
God the Holy Spirit: "There are diversities of gifts, but the same Spirit. There are differences of ministries, but the same Lord. And there are diversities of activities, but it is the same God who works all in all. But the manifestation of the Spirit is given to each one for the profit of all: for to one is given the word of wisdom through the Spirit, to another the word of knowledge through the same Spirit, ... But one and the same Spirit works all these things, distributing to each one individually as He wills... Now you are the body of Christ, and members individually. And God has appointed these in the church: first apostles, second prophets, third teachers, ..." (1 Corinthians 12:4-8, 11, 27-28)

If God has not appointed and empowered a person to teach about Him, should that person be appointed and educated by humans to teach about Him?
 

If a person has been appointed and empowered by God to teach about Him, does that person need educational degrees to teach about Him?
 

What do most churches require their new pastor to have attained?
A "Master of Divinity" from an accredited seminary.

How Biblical is this requirement and what should be done about it?
See Master of Divinity.