What is the test for unanimous verdict in a criminal case?

"In a criminal case, a jury verdict must be unanimous. [Citations.] . . . Additionally, the jury must agree unanimously the defendant is guilty of a specific crime. [Citation.] Therefore, cases have long held that when the evidence suggests more than one discrete crime, either the prosecution must elect among the crimes or the court must require the jury to agree on the same criminal act." (People v. Russo (2001) 25 Cal.4th 1124, 1132.)

The " 'requirement of unanimity as to the criminal act "is intended to eliminate the danger that the defendant will be convicted even though there is no single offense which all the jurors agree the defendant committed." [Citation.] . . . "The [unanimity] instruction is designed in part to prevent the jury from amalgamating evidence of multiple offenses, no one of which has been proved beyond a reasonable doubt, in order to conclude beyond a reasonable doubt that a defendant must have done something sufficient to convict on one count." [Citation.]' " (People v. Norman (2007) 157 Cal.App.4th 460, 464-465 (Norman).)