The main thing for me is that the contents of flatulence and BO were not made by the animal themselves. They were made by symbiotic bacteria.
Regarding plants taking in O2 and expelling CO2, to my knowledge this only happens at night, and the plant is not actually using the O2. It's just concentrations naturally equalizing while it waits for the sun to come back. Do some plants actually have a use for O2? That's out of my wheelhouse.
Anyways, I can see the flatulence argument, since both are a result of a "feeding" behavior, but there's not a lot else in common.
The main thing for me is that the contents of flatulence and BO were not made by the animal themselves. They were made by symbiotic bacteria.
Regarding plants taking in O2 and expelling CO2, to my knowledge this only happens at night, and the plant is not actually using the O2. It's just concentrations naturally equalizing while it waits for the sun to come back. Do some plants actually have a use for O2? That's out of my wheelhouse.
Anyways, I can see the flatulence argument, since both are a result of a "feeding" behavior, but there's not a lot else in common.