“When we ingest other living things, the DNA of those living things (fruits, vegetables, nuts, meats, etc.) just happens to be compatible with our DNA so that cellular respiration can take place.”
Um….no. The DNA of our food does not make it to the cell for cellular respiration. CR needs glucose and oxygen.
Digesting the plant, meat, is what produces the glucose. Not the DNA.
"If it were not for the fact that our DNA is so akin to all other living things, we could not eat. If we could not eat, we would die.”
No. With respect to cellular respiration, we just need glucose. If our DNA was completely unlike a banana’s, but it still produced glucose, we’d eat it.
“Is the process of eating and cellular respiration the result of a mere fluke of evolution?”
WOuldn’t call it a ‘fluke.’ I mean, as you say, life depends on it. So way, way, way back, life found a use for that trait and exploited it.
“Alternatively, could it be that a common Designer made certain that the process of eating and cellular respiration would function in such a precise and perfect manner?”
Define ‘precise’ and ‘perfect’ in this context, please.
“Which answer appears to be the most probable to you?”
Well, you mistate the one you don’t want to be probable, but still any answer that includes a magic sky fairy is less probable.
“If the supposed cosmic”
Cosmic? Ah. You think the theory of evolution includes the Big Bang.
“and random happenstance of evolution was the real reason that all living things exist,”
Not random. You have no idea how your efforts to sound knowledgeable make you look foolish, do you?
"why, when, and how did this happenstance mechanism decide that living things needed to eat anything in the first place?”
There may not be a ‘why,’ not in any way you’d accept.
And the entire history of evolution is trial and error. The errors are fatal, and pretty much final, what? And the mechanism to ‘decide’ is that the ones that don’t die get another chance.
"Would it not be odd that evolution should come up with the idea of food and energy creation through cellular respiration?”
No. ‘Odd’ refers to things that would be rare. The odds of evolution coming up with actual cellular respiration, not your version, is 1:1.
“Cellular respiration is an astoundingly complex, energy-expending system.”
I think you’re confused. CR is what produces energy. For the body to expend. And that it astounds you is not a mark against it. But a complexity argument IS a mark against you.
"Yet in order for life to be sustained, living things must have other living things to ingest.”
Most life forms CURRENTLY occupying the planet. But not all.
“What an odd thing for a mere cosmic coincidence to develop, by random generation.”
Simple life forms found that ingesting other life forms was more efficient than other ways of getting energy out of the environment. And evolved to other life forms. That’s what evolution means, changes, right? You’re kinda stuck on the idea that everything goes back to the begining alongside each other.
“Is it not a strange convenience for evolution that all living things have such unimaginable DNA similarity that cellular respiration is possible?”
No. Because that’s not what happens.