What is the test for jury unanimity in a criminal case?

"In a criminal case, a jury verdict must be unanimous. . . . 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.] [] 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.' " (People v. Russo (2001) 25 Cal.4th 1124, 1132.)

The prosecution's election may be accomplished by means of opening and closing argument. (See People v. Mayer (2003) 108 Cal.App.4th 403, 418 [prosecutor's opening and closing arguments constituted "an election for jury unanimity purposes"]; People v. Hawkins (2002) 98 Cal.App.4th 1428, 1455 ["Because the prosecutor's opening argument elected what conduct by defendant amounted to the crime charged, we conclude that no unanimity instruction was required."].)