Zero, first or second conditional?

[Katharsis]

Hi. I am hoping to get answers for the next problem of mine;
we had a test today at school and one of the tasks was also a task where you had to fill the gaps with suitable conditionals (0, 1. and 2.).
I had some problems with the following two examples:
If the cat (hide)_______ in the tree, the dog ________ (not find) it.
Is at this particular example possible to use only first or also zero conditional?
And the next one:
It's so noisy in here. Even if the students ________ (listen) carefully, they _______ (not hear) the woodpecker.
Second or first conditional with this one?

Thanks in advance for answering.

[5jj]

Welcome to the forum, Katharsis.

If the cat (hide)_______ in the tree, the dog ________ (not find) it.

Moderately natural possibilities are:

If the cat hides in the trees, the dog can't find it. (general time)
If the cat hides in the tree, the dog won't (be able to) find it. [future possibility]
If the cat hid in the tree, the dog wouldn't (be able to) find it. [future hypothetical]
If the cat had hidden in the tree, the dog wouldn't have found (/wouldn't have been able to find) it. (past counterfactual)

It is possible to say the following, but pretty unlikely that we we would:

If the cat hides in the trees, the dog doesn't find it. [general time]

It's so noisy in here. Even if the students ________ (listen) carefully, they _______ (not hear) the woodpecker.
Second or first conditional with this one?

Moderately natural possibilities are:

Even if the students listened/were listening carefully, they wouldn't (be able to) hear the woodpecker.
Even if the students had listened/been listening carefully, they wouldnt have heard/wouldn't have been able to hear the woodpecker.