Simplify the following text for a Grade 6 native English-speaking person.
Original: It stretches between 158 Â W and 103 Â 24 ` W. The inclusion of the area between the Rockefeller Plateau and Eights Coast is based upon the leading role of Rear Admiral Richard E. Byrd in the exploration of this area .
Simplified: It stretches between 158 Â W and 103 Â 24 ` W. The area between the Rockefeller Plateau and Eights Coast is included . This is because Rear Admiral Richard E. Byrd had an important role in its exploration .