Which island groups form the Ratak and Ralik chains of the Marshall Islands?

The Marshall Islands are composed of more than 1,200 islands and islets organized into two parallel chains of coral atolls that extend northwest to southeast across the central Pacific Ocean:1

• Ratak Chain: Known as the "Sunrise" chain, this group is located to the east. It includes Majuro atoll, which serves as the capital of the republic.12
• Ralik Chain: Known as the "Sunset" chain, this group is located to the west. It includes Kwajalein atoll, the largest atoll in the group.1

The two chains lie approximately 125 miles (200 km) apart.1