claim: Heroes has had 7 seasons.
evidence: Tetramethylguanidine is an organic compound with the formula HNC -LRB- N -LRB- CH3 -RRB- 2 -RRB- 2 .. organic compound. organic compound. This colourless liquid is a strong base with a higher pKa than typical amines .. base. base ( chemistry ). It was originally prepared from tetramethylthiourea via S-methylation and amination , but alternative methods start from cyanogen iodide .. cyanogen iodide. cyanogen iodide