Is the blessing AFTER eating a Torah or rabbinic obligation?
Birkat Hamazon (grace after meals) is a Torah commandment, derived from Deuteronomy 8:10. Before-eating blessings are rabbinic.
Question 2
Who composed the standard texts of all blessings?
The Rambam attributes all blessing texts to the Anshei Knesset HaGedolah — led by Ezra — who established the uniform format used by all Jews.
Question 3
You're not sure if you said the blessing after eating bread. What do you do?
Torah-level doubt: repeat. Birkat Hamazon is Torah-obligated, so a doubt means you must say it again. Contrast with before-eating blessings (rabbinic), where doubt = don't repeat.
Question 4
Benefiting from this world without a blessing is compared to:
The Talmud (and Rambam) use strong language: enjoying God's world without acknowledging Him is like theft. The blessing is the "payment" that makes using the world legitimate.
Question 5
Are women obligated in blessings?
Blessings obligate everyone: men, women, freed slaves, and children who understand. No gender exemption.