Final answer:
The North Sea contains oil and natural gas resources that are important to the economies of the United Kingdom and Norway.
Step-by-step explanation:
The sea that contains oil and natural gas resources and is important to the economies of the United Kingdom and Norway is the North Sea. Petroleum and natural gas deposits were first tapped in the 1970s. Norway and the United Kingdom are the major stakeholders in these resources, with Norway holding the bulk of the rights.