1. why was concrete better than stone for building in the roman empire? a. it was more flexible than stone when dry. b. it was heavier than stone when dry. c. it was lighter and easier to use than stone. d. it was stronger and more durable than stone.

What was piaget's explanation as to why preschool-age children in the preoperational stage make errors on tasks requiring conservation? a) preschool children's tendency toward centration prevents them from focusing on other relevant features of a situation b) preschool children have not yet developed numerical understanding; therefore, different amounts are meaningless c) preschool children's neural-visual network is not fully matured d) preschool children have not lived long enough and accrued enough experience to know the difference between quantities