Brandon and Jacob are identical twins. However, Brandon had a finger damaged in an accident, so even if you couldn't tell them apart from a distance, once you saw the finger you knew who was who. This difference is a characteristic of their

a. genotypes

Approximately 87% of all strokes are the result of ____

a. reduced blood flow b. blood vessels bursting c. leakage of blood into the brain d. vascular cognitive impairment

The two common fears of infancy, separation anxiety and stranger anxiety, reflect the baby's preference for

a. easy temperament. b. familiarity. c. social referencing. d. learned helplessness.