When does sibling conflict peak?

Lisa has been growing a bean plant for preschool. When nighttime comes she tells her mother that the plant must come inside at night because it is afraid of the dark

By attributing human thoughts and feelings to her plant, Lisa is exhibiting Piaget's concept of ______. animism assimilation reversibility egocentrism

The two sources of variability in a three-group experiment are

A) between-groups variability and error variability B) extraneous variability and nuisance variability C) between-groups variability and extraneous variability D) participant differences and experimenter biases