The answer to this question is A. recycling petroleum-based products conserves resource.GOOD LUCK AND HOPE IT HELPS U
Answer:
d) a wall that was built as a boundary but is no longer considered a boundary
Explanation:
Take the Berlin Wall for example, it is a relic boundary because it no longer splits Germany into East and West Germany.
The definition for a relic boundary is a boundary that no longer exists as a boundary just a cultural landscape.