TOEFL Reading: ETS-TOEFL阅读机经 - WZ4Y3J1MM6Y32483L$

According to paragraph 3, what is one reason that scientists use flotation A. To estimate the fluid content of ancient plants and seeds B. To identify the sediments in which ancient plants grew C. To learn about the climate of places where ancient plants grew D. To determine whether the remains of ancient plants and seeds have carbonized