'bedecken' vs 'zudecken'
What is the difference between bedecken and zudecken?
Is reagieren auf (+A) equivalent with eingehen auf (+A)?
First of all, "bedecken" is a tiny little bit more formal than "zudecken". There's really next to no difference at all. Here's my guess (you know it's hard to analyse your own language sometimes :) )
zudecken: preferredly for covering something with one thing: to cover sth. with a blanket, to cover a pot with a lid. It's more about the action of covering.
bedecken: preferredly for sth. covered in sth., more focussed on the object: a landscape covered in snow, in a recipe: to cover the lasagna with a layer of meat sauce.
"reagieren" is only "to react (to sth./sb.)", while "eingehen auf" means that you consider their suggestion/wish/plea and either act according to it as well, or at least you discuss it and show some understanding before you refuse. ("Er geht auf ihren Vorschlag ein" could, in my opinion, mean either, equally: he accepts her suggestion, or he only discusses it.)
Edit: It happens rather often that Duo doesn't show any previous answers and I only realise they're there after I've sent my own one...
Like stepintime already wrote it is not that easy to explain these tiny differences. You've got already a very good explanation so just let me give you a few sentences how we use these words.
bedecken: Schnee bedeckte das Spielfeld am Freitagmorgen. Die Frau bedeckt ihr Haar mit einem Tuch.
zudecken: Er sagt 'Gute Nacht', deckt seinen Sohn (mit der Decke) zu und verlässt das Zimmer. Den Teig zudecken und kühl stellen.
reagieren auf: Der Hund reagiert auf den Befehl 'gib Laut' und bellt.
eingehen auf: Du musst auf Deinen Freund eingehen, versuchen ihn zu verstehen, um ihm helfen zu können.
Best regards Angel
Because it's the direct object of the verb: "Cover the dough and put it in a cool place!"
It uses the infinitive as a kind of impersonal command -- this usage is particularly common on signs and in instructions (including recipes), where no specific person is being addressed.