What is the burden of proving every element of the charged offense?

In a criminal case, due process requires the prosecution to prove every element of the charged offense beyond a reasonable doubt. (In re Winship (1970) 397 U.S. 358, 364.) And when the case is tried before a jury, they must decide whether the prosecution has carried its burden in that regard. (Sandstrom v. Montana (1979) 442 U.S. 510, 520-523.) Therefore, trial court instructions that require the jury to make presumptions that effectively establish a disputed element of the charged offense are unconstitutional. (Ibid.) The problem with such mandatory presumptions is that they

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undermine the presumption of innocence and invade the core factfinding function of the jury. (Ibid.)