i need answers

Why does nodding of the head signify Yes and shaking of the head No?

What is time?

Why, if two wrongs don't make a right, do two negatives make a positive in mathematics?

What, exactly, is it about good jokes that makes people laugh?

Does thought require language?

How, if at all, does a person's way of deciding between right and wrong change from the age of two to your age?