The concrete operational stage of cognitive development lasts from approximately

Hermann von Helmholtz's explanation of color vision is called the ______ theory

a) opponent-process b) additive color mixing c) trichromatic d) reductive color mixing

According to Levinson, people around the age of 40-45 move into a period/time of questioning called ________ and focus on the finite nature of life where they begin to question everyday fundamental assumptions

a) midlife crisis b) midlife transition c) generativity-versus-stagnation stage d) normative-crisis models