The stimulant in tobacco smoke which gives cigarettes their "kick" is ______

According to the research on the use of diagrams in problem solving,

a. diagrams are often helpful because they can convey information in a clear way. b. a hierarchical tree diagram is a list of steps that must be followed in solving a problem. c. the most effective way to use diagrams is to construct a matrix representing all possible combinations of options. d. people seldom solve problems by using diagrams, because verbal representations are much more appealing.

A technique for teaching reading comprehension strategies that reflects Vygotsky's theory of development is

A) cooperative learning. B) accommodation. C) assimilation. D) reciprocal teaching.