Why Do Biologists Believe Glycolysis Evolved Before the Krebs Cycle

Multiple Choice

Why do biologists believe glycolysis evolved before the Krebs cycle and the electron transport chain?

A) Glycolysis occurs in the mitochondria, which all organisms have.
B) Glycolysis requires oxygen, which was one of the first elements on Earth.
C) All organisms use glycolysis; not all use the Krebs cycle and the electron transport chain.
D) Glycolysis is the most efficient at producing energy.