There are Creationists who teach that before the fall, all animals were herbivores because sin had not yet entered into the world, therefore bring death. That is of course based upon an interpretation of the Bible, reading in part from Romans 12. "Therefore, just as sin entered the world through one man,
and death through sin, and in this way death came to all people, because all sinned". There are other verses which speak about sin being what brought death into the world.
So, I believe that there are Christians who believe that before the fall, animals did not kill each other and were all herbivores. They teach that humans were to be vegetarians.
Death Before Sin?
As you can see, they get around this issue of plants being alive, by saying plants are not alive.
"Many species of life cannot survive for even three hours without food, and the ingestion of food requires at least the death of plants." This is, of course, true, except that the Bible never ascribes to plants the status of "life," (nor to the "lower" animals, for that matter)."
They then go on to argue that only humans, and only certain animals are to be considered "alive" (why not all is unclear). Of course, all of that is utterly absurd.
My point is, this is the problem you get into when you are a biblical literalist. One has to mangle and twist and distort reality to fit one's tortured reading of the Bible this way.
Oh, so you believe plants aren't alive because they don't have red blood cells? Does this mean that animals with yellow blood aren't alive? What about spiders?
These Animals Have Blue or Yellow Blood
So, if you then accept that all of these are alive because they have a fluid running in their bodies that carry oxygen to the cells to keep them all alive, and it doesn't need to be red, but just serve that function, then why aren't plants considered alive when they have
liquid chlorophyll? Isn't that "blood" just as much as hemoglobin? Does it serve the same purpose in keeping the plant alive?
But if that isn't sufficient, then why do you differentiate between live plants and dead plants? Would you eat a dead leaf of lettuce, or a dead carrot, all decemated and drained of all life? In other words, would you eat
garbage?? Where would the energy come from to sustain your body then?
As I said, the Bible is not a book of science. It's not meant to be one, and certainly shouldn't be taken to challenge science with. That only leads to confusing reality, calling some animals alive, and others not, and imagining plants lack life. That's goes again all reasonable faith. It is confusion.