What percentage of babies did Thomas and Chess find met their definition of "difficult" babies?

Growth and development in infancy proceeds from the head downward, which is known as the ____

a. head first, body second principle b. cephalocaudal principle c. proximodistal principle d. top-down principle

Powers et al. (2009 ) examined relations between reported childhood maltreatment, depression in adulthood, and perceived social support from family and friends. The researchers used a(n) _______ design and found that:

a) correlational; childhood emotional abuse and neglect were more predictive of depression than sexual or physical abuse. b) correlational; perceived friendship support appeared to protect women against depression despite childhood maltreatment. c) experimental: childhood emotional abuse and neglect were more predictive of depression than sexual or physical abuse. d) A and B only.