Is "отвечать на" a standard construction? Why can the sentence not hold the same meaning without "на"?
It is a standard construction. The English verbs "look" and "listen" work in the same fashion: you have to say "look at" and "listen to" something, even though it does not make much sense in some other languages (for example, Russian agrees on "look" but keeps "listen" a transitive verb).
You use "на" with "отвечать" to mean to answer to anything, such as a question, call, or email, but not with people. When answering people, you use the dative: Я отвечаю тебе/Даше/студенту -- I am answering you/Dasha/student
The expression "to answer to" means to be a subordinate of someone or some authority. e.g. "He answers to me directly."
In this case, the Russian for "to answer to" is подчиняться. Он подчиняется непосредственно мне. Он напрямую подчиняется мне.
Saying "answer to a/the question" when "answer" is being used as a verb sounds unnatural to my ear. So I would say no.
I checked a bit. Feels like that confusion I had came from the fact you say The answer to the question, but you don't say I answer to the question.
Yeah, it's a transitive verb; it doesn't take a preposition except as a verbal noun.
I understand that in this sentence, after " на ", we used the accusative case and not the prepositional . I fail to perceive the motion that is indicated. Being " отвечаю на " a standart construction i will always remember that in this case we also use accusative.
It sounds like she's saying otvicheyu. Is the a turning into a e said by native speakers?