I think your answer would be c i looked it up on google
Answer:
air conditioning.
Explanation:
The artic is like air conditioning for the northern hemisphere. If it goes away it could change the weather conditions and climate patterns. If the artic moves away it could also lead to floods and droughts which are more catastrophic. This helps transformation of the environment.
If you are talking about arks for construction, the answer would be "The point or line at which an arch or vault begins to curve".
