This, though a broad statement, is true as far as I can tell.
Sewage holds toxic microbes and contains a mixture of suspended impurities. When these impurities hit drinking water microorganisms begin to deteriorate the water, and uses up the dissolved oxygen with the microorganisms, making these water dangerous to drink from. Major impacts of this can include giardia, salmonella, cryptosporidium, and E. coli.
The breakdown of carbohydrates into glucose. Glucose use to obtain energy (ATP) for the human cellular respiration by the steps glycolysis, acetyl CoA and kreb cycle. In glycolysis, ATP is use to generate greater ATP called the ATP debt. Fat (lipid) and protein (amino acid) also can give human energy call gluconeogenesis but only when critical condition only.
One of the major elements of natural selection is that all species have genetic variation. Natural selection is a process when organisms adapt better to their environment. It is an essential key in evolution. There is a change in phenotype of a population over time.
It would change too because the reaction is based on the enzyme.