I assume that the question refers to the political affiliation of the Islands (They are Islands in the Mariana Trench, in the Pacific Ocean, south of Japan) - they are politically linked to the US - the correct answer is a). For example the Mariana islands have a commonwealth status within the US.
Answer: The transfer of the minerals of the earth to living organisms and then back to the earth again is called a cycle
Earths history of climate is easily understandable through the study of existing rock and shells aquatic organisms. Rocks came into the earth million of years ago. So, the study of age determinism of rock gives an idea of climate through which it has come across. This is called paleontology.
Explanation:
In studying Earth's history of climate scientists take help of available rocks and body parts of aquatic animals. As rocks are the most eventful findings on the earth's surface which has come across million of years and witnessed several changes. These study if changes in rock is called paleontology.
Shells of aquatic animal which found in underwater are also a good evidence of earth's history of climate. It is found in the layers of sedimentary rock which is soft in nature and found in layerwise. Where all the organism became fossil after death and its body parts remains in the form of stone.