there aren't many enzymes in food, mainly in fruits, the enzymes in friuts are very similar to ptylin found in the mouth that help break down sugar, they do not need to be ingested before they activate, a proof of this is the apple test, buy an apple, take a bite and leave it without covering it for a few minutes, you'll notice that the bitten part starts turning yellowish brown because the enzymes in the apple are already breaking it down.
In summary, they do not need to be ingested before activation, and the major characteristic of an enzyme is that they do not change after they react with (breakdown) food, so they are in the same form before and after they finish breaking down the food.
For the answer to the question above, the peripheral nervous system governs <span>all structures outside the brain and spinal cord. Peripheral nerves branch from the spinal cord through the foramen transversarium of each vertebrae. I suppose the structure it would not affect is the brain itself since cranial nerves are responsible for brain activity. Also, the spinal cord would also be unaffected since it is just a cylindrical bundle of nerve fibers that allow the connection of the peripheral nerves to the brain.</span>
Human and apes have 5 fingers that are used for grasping objects, so they have the same function, but they also have a common ancestor and are closely related, that means that this is an example of homologous structures. In evolutionary biology, the term homologous structures means that there are organs and skeletal elements of animals and organisms, that by virtue of their similarity, suggest their connection to a common ancestor.
