Well, because you asked about grammar/spelling errors? In your signature, you spelled "errors" as "erros" without the last "r".
Now, not really to laugh at you, just the situation, I can't help but giggle at the fact that you asking about errors had an error.
Still, with English being a second language, let me say you do very well with grammar and spelling over all.
Now, to a question: When it comes to science, which field interests you most? What attracts you to it? What might convince you not to pursue that field?