[quote]Are Precursors just giant Graveminds,[/quote]The Primordials were ancient Graveminds. It is unknown if all Precursors are Graveminds. [quote]if so is it them who created the flood for defense against the Forerunners?[/quote]Yes, but no. They were created to regenerate the Precursor's past forms. However time corrupted them and the Flood was born. [quote]Also, the Captive from Primordium, or the Precursor, said "[i]And, our answer is at hand.[/i]". To what was he referring to?[/quote]The destruction of the Forerunners and the oppression of all life.