What are the essential elements of possession of a controlled substance?

"The essential elements of possession of a controlled substance are 'dominion and control of the substance in a quantity usable for consumption or sale, with knowledge of its presence and of its restricted dangerous drug character. Each of these elements may be established circumstantially.' " (People v. Palaschak(1995) 9 Cal.4th 1236, 1242 (Palaschak).)