Although hannah understands the principle of conservation and basic mathematical operations, she has difficulty understanding hypothetical questions and attempts to solve problems unsystematically, by trial and error. according to piaget, hannah has not yet attained the cognitive skills characteristic of the stage.

sectionalism continues to divide the nation as the question of slavery being allowed in the mexican cession became a problem. -the results of the mexican war spark secession in the south because the north did not want to allow slavery in the territories won.

answer; chemical substances that affect our psychological state;