Why is evidential burden essential, and why does it require attention on which party to take burden of proof?

What are actus reus elements does this offence have and what type of actus reus elements are they? Now consider the offences of (a) sexual assault ('sexual intercourse without consent') and (b) assault police ('assaulting a police officer in the execution of his or her duty').

The subjective, strict, and absolute standards. How do they differ from one another?

What are reason for the Crown had not rebutted the presumption in favour of a subjective mental element for the 'prohibited substance' actus reus element?

If that presumption had been rebutted, what further presumption would have arisen?

What considerations would the Court have taken into account when assessing whether the Crown had rebutted this further presumption?

What reason for requisite mental element for the possession offence was subjective?