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

In People v. Ortiz (2012) 208 Cal.App.4th 1354, our colleagues in the Fourth District recently summarized the applicable law: "In a criminal case, a defendant has the constitutional right to a unanimous jury verdict. (Cal. Const., art. I, 16; People v. Russo (2001) 25 Cal.4th 1124, 1132 (Russo).) Furthermore, 'the jury must agree unanimously the defendant is guilty of a specific crime.' (Russo, at p. 1132.) '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.] [] 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." ' (Ibid.)