B. cerebellum, the cerebellum is responsible for all these as well as maintaining muscle tone
Microbes. Bacteria, for example, convert nitrogen and carbon dioxide from the air into usable components that plants and animals can use as essential building blocks. A loss of all microbes would be terrible news for living organisms that can't create or take in these essential nutrients on their own.
You can physically see the phenotype of a trait, but not the genotype.
