Learn Portuguese (Portugal): Apresentei a demissão hoje porque estou insatisfeito. - I submitted the resignation today because I am dissatisfied.

In Portuguese, formal documents like a resignation (a demissão) or a complaint are usually 'presented' (apresentadas) or 'delivered' (entregues). While the verb submeter exists, it is mostly used for online forms, applications, or submitting to an authority's judgment. For resigning, apresentar a demissão is the standard fixed expression.

Why does the sentence use a demissão (the resignation) instead of a minha demissão (my resignation)?

Portuguese frequently drops possessive pronouns (like minha) when the context makes it obvious whose action or possession it is. Since the verb apresentei already shows that you are the one doing it, saying a demissão sounds completely natural and avoids redundancy, though a minha demissão would not be strictly wrong.

Since this lesson focuses on não que and the subjunctive mood, why is porque followed by the indicative verb estou here?

The conjunction porque (because) introduces a real, affirmed cause, which requires the factual indicative mood (estou). You only use the subjunctive for causes when you are actively rejecting a presupposed reason, which is what triggers phrases like não que (not that) or não porque (not because). This sentence gives the true, accepted reason, so it stays in the indicative.