Why are biogeochemical cycles important? Earth is a closed system. That means the amount of rocks, metals, carbon, nitrogen, oxygen, and water on Earth ( Blank) . So, it is essential that biogeochemical cycles
(Blank) these materials as they move through Earth's subsystems.

These cycles are called biogeochemical cycles because they include a variety of biological, geological, and chemical processes. Many elements cycle through ecosystems, organisms, air, water, and soil. ... The biogeochemical cycles transport and store these important elements so that they can be used by living organisms.

chemical digestion occurs in the stomach were hcl and pepsin forms chyme, the mouth in which salivary amylase breaks down starch to form bolus, and the small intestine specifically the duodenum.