Fill in the missing eras and periods in the geologic time scale below.

This active feature of earth's crust in building mountain ranges as well as islands. this feature is a a) cavern. b) earthquake. c) mountain. d) volcano.

The peak wavelength for the blackbody curve of a star is in the uv range. assuming the radiation from this star can reach earth, would you be able to see it?

The name of the ion, s2-, is: sulfurous ion sulfide ion sulfur ion sulfate ion