Select the correct answer from each drop-down menu. Complete

Last updated: 7/9/2022

Select the correct answer from each drop-down menu. Complete the sentences to explain how photosynthetic organisms changed our lives on Earth. The _____ in the atmosphere that all living beings depend on was generated by cyanobacteria during the Archaean and Proterozoic eras. The presence of this substance is what makes _____ possible on Earth.