Why is it significant Jesus would select twelve Apostles?

It is significant that Jesus would select twelve Apostles because each Apostle seemed to represent each of the twelve tribes of Israel. Also, it marked a beginning of a new community of faith, a new Israel.

What was Jesus' relationship with his disciples called Apostles like?

Jesus' relationship with his disciples called Apostles was based on: Jesus' Apostles sharing his power, and how they continued to preach, heal, and make new disciples through the baptism after Jesus' death.

Who are the Apostles?

The Apostles were people who responded to Jesus' message and followed him.