A、Toillustrate that theembryofossilsarequiteadvancedin theirdevelopment.
B、To explain why the fossils are well preserved
C、To explain why the fossils are well preserved
D、To prove thatichthyosaursare marineanimals
Task 116.Paragraph①17.Paragraph ②18.Paragraph ③19.Paragraph④20.Paragraph⑤A. Rich Resources of the StateB. Connections With the Outside WorldC. Transportation ProblemD. The Natives of the LandE. Position and Cold ClimateF. LandandPopulation