How does the release of carbon dioxide by micro organisms benefit plant life

What's the waste product of electrons and pyruvate combining in fermentation?  

Which statement describes characteristics of planarians? a they live in oceans, are parasites, and reproduce only sexually. b they live in fresh water, are parasites, and reproduce only asexually. c they live in oceans, are free living, and reproduce sexually and asexually. d they live in fresh water, are free living, and reproduce sexually and asexually.

The law of thermodynamics states that energy can't be created or destroyed. to natural sources of energy on earth are the