Assessing opportunity cost involves?

Which type of market produces the highest level of output at the lowest price to consumers?

Lava and other matierls luanced from a volcano and into the air are referenced as

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?