Which of these correctly defines the poh of a solution? the log of the hydronium ion concentration the negative log of the hydronium ion concentration the log of the hydroxide ion concentration the negative log of the hydroxide ion concentration

POH measures how basic a solution is.
pOH scale can be calculated as follows
pOH = -log[OH⁻]
[OH⁻] is the hydroxide ion concentration. 
therefore pOH is the negative log of the hydroxide ion concentration. 
correct option is the 4th option.

The  grandmother cell  is a hypothetical  neuronthat represents a complex but specific concept or object.[1]  it activates when a person "sees, hears, or otherwise sensibly discriminates"[2]  a specific entity, such as his or her grandmother. the term was in use at least as early as 1966 amongst staff and students in the department of experimental psychology, university of cambridge, england. a similar concept, that of the  gnostic neuron, was proposed two years later