I give you a group of three. One is sitting down, and will never get up. The second eats as much as is given to him, yet is always hungry. The third goes away and never returns.
A man is leaving on a business trip and stops by his office on the way to the airport. The night watchman stops him and says, “Sir, don’t take that flight. I had a dream last night that your plane would crash and everyone would die!” The business man cancels his trip and sure enough, the plane crashes, killing all the passengers. The man gives his watchman a $10,000 reward for saving his life, then fires him. Why?
A penguin. If all four walls face north the house must be at the southernmost point of the earth. Really, any native antarctic bird would work.
This brain teaser is quite similar to the guy whose house walls face south and sees a bear, then you’re asked the color of the bear. The bear would be white (a polar bear) as they’re the only bears indigenous to the north pole. A lawyer would claim it’s all circumstantial evidence and the bear could be an imported brown bear. The lawyer makes a valid point.
The typical answer to this is “I am,” but some argue that it’s not a complete sentence. However, if someone asked a man named Rupert if he was Rupert, he could reply, “I am” and it would make a complete sentence in my book.
But that’s not the whole answer. There is an even shorter sentence using an imperative with an implied subject (how’s that for an English terminology-filled sentence?) With “Go,” the “you” is implied. For example, if your wife wanted you to go with her to pick up some donuts and you were busy, she might say, “I really want to get some donuts, I’m starving!” and you might reply, “Go!” The implication being you never wanted to get donuts in the first place because you like ice cream more anyway and if you’re busy you’re probably doing something worthwhile and important and can’t be disturbed for such trivial matters as acquiring sweet pastries with holes in them, no matter how much of a waste of time your wife says your pursuits are. In short, “Go” is the shortest sentence in the English language that also has the longest implied meaning. Do you want to get get some ice cream? Go!
Ava pointed out in the comments that No is another viable alternative.