Anything that can't be absorbed by the gut into the bloodstream will continue on its journey through the digestive system. This includes roughage. Eventually, the undigested material will pass out as faeces.
You wouldn't be able to digest starch.
No, feces is a waste product. It is only what an organism cannot digest. Organisms who regularly eat meat will have the enzymes to digest the proteins and dissolve any tough portions. Human feces contains substances that we don't have the enzymes to digest such as cellulose or fiber.
No, see as the unicellular organism digest the food it turns it into energy,
No, you cannot digest fingernails. They are made of a tough protein called keratin, which your digestive system cannot break down. Instead, fingernails would pass through your digestive system and be excreted in your stool.
People cannot digest cellulose
No, it's keratin, mammals cannot digest it.
Hyenas can digest anything except metal
You digest it.
Animals must digest food to receive the essential nutrients that the particular organism needs to survive.
Animals must digest food to receive the essential nutrients that the particular organism needs to survive.
Fiber
You digest it.