Why was literacy a prime concern in the massachusetts bay colony

The answer is "so people could read the Bible and protect themselves from sin"

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)

2018 means 2018 ce or common era

there have been other eras too including bce, which included way more years.