This may be a dumb question but what is the difference between meu and minha? Teu and tua and teu and seu? And so on...
meu, teu, seu, nosso etc are used with masculine words. minha, tua, sua, nossa are used with feminine words.
Why isn't there a definitive article before the possessive?
It is opitional for possessive adjectives. Here you can use or omit it.