hello, i am having trouble again with grammar.

what is the grammar reason for having the preposition ' на ' the sentence "я отвечаю всем на вопросы"?

я отвечаю всем на вопросы = the syntax here really confuses me. what does "на вопросы " mean in this sentence? does it mean "i am answering everyone (everyone is questioning me)?" or "i am answering the questions to everyone (here i mean everyone is being questioned)?"

я отвечаю всем вопросы = "i am answering questions to everyone (i am replying to people by asking questions)?" or is this nonsense?

also, please tell me if i have the correct translation of the following sentences:
я отвечаю все = i am answering everything
я отвечаю за все = i am answering for everything
я отвечаю всем = i am answering everyone
я отвечаю вопросы всеx = i am answering the questions of everyone

thank you!