whether or not; can it or can't it; is it possible?
能 · 10 strokes
Pictograph of a bear. Based on the original meaning "bear". The meaning of this character has shifted over time to mean "strong" and "ability, power". Original form of 熊.
否 · 7 strokes
Originally the same character as 不. Distinguishing component 口 was added later to the character when it took on the meaning "not". 不 represents the sound.