Because so few 251-million-year-old rocks are exposed, Becker s investigations took two years to complete, but the scientists analyzed soil and rock from Permian-Triassic outcrops in Japan, Turkey and 
(so few 251-million-year-old rocks; are exposed; ) (Becker s investigations; to complete; ) (the scientists; analyzed; soil and rock)
so few 251-million-year-old rocks Becker s investigations the scientists
are exposed to complete analyzed
soil and rock