1. Rumen: The largest compartment, where bacteria break down plant matter.
2. Reticulum: This compartment sorts food and helps move it back to the mouth for further chewing.
3. Omasum: This compartment absorbs water and further breaks down food.
4. Abomasum: This is the "true stomach" where digestive enzymes are released, similar to a human stomach.
So, while the abomasum is part of a cow's complex stomach, it's not the first, second, or third compartment!