Damaged nerves in the spinal cord do not regenerate themselves natural

Dear imawolf,

My lupine friend, I am happy to respond.

This is a brilliant question. I don't know the source.

Here's the prompt & question:
Damaged nerves in the spinal cord do not regenerate themselves naturally, nor even under the spur of nerve-growth stimulants. The reason, recently discovered, is the presence of nerve-growth inhibitors in the spinal cord. Antibodies that deactivate those inhibitors have now been developed. Clearly, then, nerve repair will be a standard medical procedure in the foreseeable future.

Which of the following, if true, casts the most serious doubt on the accuracy of the prediction above?

Here's (A), the OA:
(A) Prevention of the regeneration of damaged nerves is merely a by-product of the main function in the human body of the substances inhibiting nerve growth.
That's a very complicated sentence. If you don't understand the term "by-product," you need to look that up and understand it thoroughly.

First, there are "substances inhibiting nerve growth" in the human body. Call these SING for short--an acronym.

The argument proposes using "antibodies" to "deactivate" the SING, to render them completely ineffective and non-functioning.

We may wonder whether "inhibiting nerve growth" is all the SING do or whether they have any other jobs.

Well, (A) tells us quite definitively that "Prevention of the regeneration of damaged nerves is merely a by-product of" SING. In other words, the SING have other jobs in the human body, their "main jobs," and "inhibiting nerve growth" is simply some that happens in addition to everything else they do. Each SING has a "main job" first, and "inhibiting nerve growth" is an extra that also happens--a by-product.

This piece of information presents a HUGE problem for the argument. We want to encourage nerve regrowth, but if we us antibodies to render the SING ineffective, then that will stop everything the SING do--it will stop all their "main jobs," as well as removing the blog to nerve regrowth.

Now, we don't know what those main jobs are, but the human body is truly miraculously designed. Three billion years of evolution have come together in producing a complex system so brilliantly interconnect and interrelated that it truly boggles our mind. Each body is a miracle packed full of a million miracles. Human beings walk around every day with no idea that their bodies are astonishing miracles beyond all reckoning.

If a substance in the body has a "main job," chances are very good that this "main job" is absolutely essential for the life and health of the body. Stopping this "main job" would have lead to dysfunction, illness, and perhaps even instant death!

Thus, shutting off the SING and their "main job" would produce devastating effects. Those side-effects are far too severe and dangerous, so this kind of treatment does not look promising after all.

Does all this make sense?
Mike