What is the primary source of energy for all
living organisms?

you didn't give any options but heres what i can tell you: an inference is likely to change based on additional observations. the latter is something that you have seen or sensed using your sensory organs while the former is like a conclusion out from what you have observed.

the answer u all are looking for is 4000000000000000000000 million years.

answer; /// the shaft of the hair consists of dead cells;