"Oui, la fille mange du pain."
French doesn't have a progressive tense (the -ing forms) like we do in English. Instead, the present tense is used for both cases: "I eat chicken" and "I am eating chicken" are translated the same way. In real life, context gives the meaning. On Duolingo, though, it's just your personal preference.
How do we know what tense we are talking about here? Warning: I suck at grammar.
Like, this could be translated as 'Yes, the girl eats bread' or 'Yes, the girl is eating bread.' Both are very different because of their tense.
Except in English they say the same thing. Thus either translation would work.
I think French speakers would understand which one you mean depending on the context. Like northernguy said, they mean the same.