Anaerobic digestion means no oxygen.
The spleen is not really related to digestion, so it pretty much just sits there and performs its normal spleenic non-digestion-related functions.
Red blood cells have only one function, which is to transport oxygen. This has no direct connection to digestion, although without oxygen the body would die, and no digestion would take place after death.
This is a digestion process in the absence of oxygen. This process however do not take place in the living body.
There are four stages: ingestion, digestion, absorption, and elimination.
Dissolved Oxygen can diffused through the membrane in digestion system by concentration gradient however the amount absorbed should be minimal or negligible.
Water remains water throughout the digestion process. It is not broken down into oxygen and hydrogen.
In heterotrophs digestion provide glucose molecules.These molecules are oxidized in respiration
Anaerobic digestion
Sorry to disappoint you, but digestion DOES NOT connect photosynthesis to respiration. Photosynthesis and respiration comes from plants and animals, when the animal breathes out CO2, and they receive the oxygen when the plant inhales the CO2 and breathes out oxygen. That's it. And the cycle repeats just like that. NOTHING with digestion. Trust me.
Digestion which takes place within the cytoplasm of the organism, as in many unicellular protozoans.
Digestion, this then creates energy for the cell