Why does a number with an exponent of zero equal one?

Aphrase is shown read the phrase and give me the answer

Aquadrilateral has exactly 3 congruent sides davis claims that the figure must be a rectangle why is his claim incorrect.

Aresearcher believes increased perceived control influence the well-being of residents at a nursing home. to test this , she allowed one group of residents to have control over their daily lies, (where to eat etc) . the other group of 5 residents had these deceisions made by staff. the resident's feelings of well-being were measured on a 10 point scale at the end of a one month trial period. is there a difference on well-being?