Heterotrophic organisms require nitrogen and carbon for nutrition.The reason is primarliy based on the theory primordial soup. It also have a lot to do with organic compounds.
90% of digestion and absorption takes place in the small intestines.
the main function of the small intestines is <span>absorption of nutrients and minerals from food.</span>
Rennin is not a factor that helps create the stomach mucosal barrier, whereas thick coating of bicarbonate-rich mucus, tight junctions of epithelial mucosa cells, and replacing of damaged epithelial mucosa cells are.