What two layers of the Earth does plate tectonic theory focus on>

Approximately how many million years older than bedrock layer b is bedrock layer d

What is the primary justification of the hypothesis that the early earth environment was void of oxygen? ( 2 points) data showing the concentrations of gases extracted from rocks fossil evidence regarding the origin of eukaryotes generally accepted atmospheric conditions molecular evidence based on evolutionary traits.

What are the answers for the following questions?