Explaining why a word is an adverb rather than adjective: example with präzise

Question

Die Immunabwehr, also die Abwehr eines Krankheitserregers oder Fremdkörpers mithilfe eines präzis(e) gesteuerten Abwehrsystems, ist eine der komplexesten Reaktionen im Körper eines Lebewesens.

The part in brackets was removed, and I am to fill it. I thought it was an adjective and put "en" but it's actually an adverb. In a previous question I asked, this sort of phenomena was explained through a difference in intended semantics refer, but I can't apply the principles there here. Could someone help?

I believe the main difficulty is that here adverb comes between noun and verb in a comma sentence which makes using the reasoning in above difficulter?

Answer 1

This has nothing to do with sentence structure. The construction [determiner] [adverb] [adjective] [noun] remains unchanged no matter the context.

There are two other issues that make this case complicated to distinguish from a normal double adjective:

• Most adverbs have unchanged distinctive forms. For instance, in "der sehr große Ball", "sehr" can only be an adverb, so it cannot apply to "Ball" directly. But "präzis/präzise" has alternate forms even as an adverb, and one of them looks like an inflected adjective (but not a form that would match the genitive singular needed in this context).

• Also, semantics often disambiguate. In the phrase "eine präzise gebratene Zwiebel", "präzise" has to be an adverb, since an onion cannot really be described as precise, but the act of frying something might be. But in this case, both the immune system and the controls could conceivably be considered precise, so the solution relies on very subtle cues.

Altogether, I'd consider this a hard puzzle, almost a trick question.