Why does it become difficult to read old fossils? a. older fossils are difficult to obtain because they’re extremely deep in the earth’s crust. b. older fossils are biologically less important than newer ones. c. older fossils provide less information about evolution. d. older fossils are only formed by sedimentation.

Global warming will produce rising sea levels partly due to melting ice caps but also due to the expansion of water as average ocean temperatures rise. to get some idea of the size of this effect, calculate the change in length of a column of water 1.00 km high for a temperature increase of 1.00ºc. note that this calculation is only approximate because ocean warming is not uniform with depth. (answer in ×10^{-3} −3 m)