What is the test for unanimity in a jury to convict a defendant of a single discrete crime?

On the other hand, unanimity is not required when a single discrete crime is based on multiple theories or acts. (Russo, supra, 25 Cal.4th at p. 1135; People v. Grimes (2016) 1 Cal.5th 698, 727-728 (Grimes).) It is only required when two or more discrete crimes form the basis of a conviction on a count. Stated another way, if the evidence shows only a single discrete crime but is unclear as to precisely how that crime was committed or what the defendant's role was, the jury need not unanimously agree on the basis. (Russo, at p. 1135.)