While the cross is central in the new testament, the old testament has as the central event the

While the cross is central in the New Testament, the Old Testament has as the central event the Ark of the Covenant.

Explanation:

The Ark of the Covenant is the supreme expression of God´s commitment to the people of Israel, which is God´s chosen people over another nations. Built in the desert under instructions given by Yahweh himself, it is present in the major events of the life of the Jewish people in ancient times as we can read in the Bible.

interdependence is when all participating groups and individuals depend on each other. if you depend on one anothers goods, you end up trading in order to get the items you're looking for. (for ex: if i have food and you have water, we trade in order to depend on each other to live)