The main source of energy for reactions that occur in all living organisms is

Sunlight.

Sunlight is used and needed in all organisms for reactions of all sorts and is shown as the main source of energy for living things as such during photosynthesis for example.

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in the year 2850, humans successfully colonized mars. the martian modules that were constructed could hold only a small population of people. it is now a century later, and the population on mars has grown to 600 people. of the current mars population, 45 people express the recessive phenotype for phenylketon- uria (pku) syndrome (pp genotype).

explanation:

protistas excret ethanol used in the manufacture of vinegar