In a series of rock layers, a geologist finds fossils of a lizard-like dinosaur and a fern-like tree in layers that are 1.0 m and 1.5 m deep. however, in a layer that is 2.0 m deep, he finds fossils of bony fish and shellfish. which explains his findings? a. the ancient sea dried up and became land. b. the ancient land area was invaded by a sea. c. an asteroid hit the area, causing the dinosaur to become extinct. d. the continent shifted to a polar region.