Those are all really good questions, but at the end of the day they don't really matter and are a matter of semantics. You could similarly ask is there anything that isn't life. Is matter a prerequisite for life? What about voids in the matter of space that shift and change over time? Is empty space alive?
You could Define life broadly to include Stars or mountains, but then you just look for a new subset and name that would include life more similar to our own.
One definition of life that I think resists scrutiny is an object or unit which contains a transferable data and an algorithm to use that data. This would separate a cloud from a tree.
there's a sliding scale, a tiny basic interpreter doesn't explain the addition and subtraction algorithms it uses either, relying on the cpu hardware for that
So maybe to be alive you can't use any external interpretation. It pushes the threshold up, but basically all cellular life decoders it's own DNA. The environment is just materials and I formation. No decoding
you run into the reprap vitamin problem: is vitamin b12 'just materials' or is it 'decoding'? but afaik all cellular life encodes its own ribosome proteins in its dna or rna, rather than harvesting ribosomes from prey, so in that sense it encodes its own decoder
I think you could argue that b12, ect are just materials in the sense that the consumer is not providing inormation for its manufacture.
In this case where manufacturing instructions are transmitted, you could have a system where neither component is consider alive by itself, but the system is.
One cell with DNA only, and another with ribosomes only would not be considered alive. However, a multicellular combination of them would be alive.
Obligate parasites will be alive in some cases, and not in others, depending on how they handle stored data (DNA), and what they rely on the host to do.
You could Define life broadly to include Stars or mountains, but then you just look for a new subset and name that would include life more similar to our own.
One definition of life that I think resists scrutiny is an object or unit which contains a transferable data and an algorithm to use that data. This would separate a cloud from a tree.