What is the value of x in the diagram below?

The length of the path between two points is what

Impressions of tropical swamp plants were observed on rocks in polar regions. the impressions were dark black imprints, which means the fossils are examples of ( 1 ) the fossils tell us that polar regions ( 2 ) ( 1 ) a. carbonization b. mineralization c. trace fossils ( 2 ) a. had tropical plants that can grow in ice b. might have had a diffierent climate in the past c. will have abundent vegitation

The graph below plots the temperature and luminosity of stars on the main sequence.