What is a multi tier timeline

How did european immigrants of the late 1800s change american society

Because of the housing bubble, many houses are now selling for much less than their selling price just two to three years ago. there is evidence that homeowners with virtually identical houses tend to ask for more if they paid more for the house. what fallacy are they making?

What happens after a star goes supernova? just wondering! [tex]supernova [/tex] answer asap i really wanna know!