What is a precursor? select one: a. a substance that is used to synthesize another compound b. a sign or symptom of a subclinical vitamin deficiency disorder c. a conditionally essential vitamin d. a substance that is recycled through the liver and intestines e. a sign or symptom of a clinical vitamin deficiency disorder?

How is anaerobic respiration affected by changes in temperature? (5 points)based on the conditions of early earth, what conclusion can you draw about the amount of anaerobic respiration that was occurring at earth’s beginning? explain your answer.(5 points)if there was a sudden drop in temperature after the evolution of the first living cells, predict how that might have affected the changes in the atmosphere and the evolution of cyanobacteria and other autotrophs. explain your answer. (5 points)