Question

1. El aqua de esos rios esta contaminada (posible)

my answer?

Es posible que ela aqua de esos rios esta contaminada.

is it el or ela agua

Answer 1

First of all, it is not "q" but "g" in the word "agua." There are accents that MUST be there. I corrected this one early today.
Es posible que el agua de esos ríos esté contaminada.

the word agua is feminine BUT for sound it uses the "el" when it is singular. el agua, las aguas

Sra