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. [Citations.]" (People v. Russo (2001) 25 Cal.4th 1124, 1132.)

"This 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.]" (People v. Russo, supra, 25 Cal.4th at p. 1132.) "For example, where the evidence proved several distinct episodes, any of which could have supported the defendant's conviction of a single count of bribery, a unanimity instruction was required. [Citation.] Similarly, a unanimity instruction was required where the defendant was charged in one count with passing 35 bad checks, because each check represented a potentially separate and independent offense, creating the possibility the jury might not have unanimously agreed that the defendant committed any single offense. [Citation.]" (People v. Sutherland (1993) 17 Cal.App.4th 602, 612.)