The correct answer appears first and is boldface.

1. a. The growth spurt occurs approximately two years earlier in girls; thus, Kristie is likely to be taller and heavier than Peter.

b. The growth spurt, which occurs earlier in girls, includes increases in height and weight.

c. Although adult males tend to be taller and heavier than adult females, adolescent girls are often taller than adolescent boys because they experience an earlier growth spurt.

d. The earlier growth spurt usually seen in girls is likely to make Kristie taller and heavier than Peter during the next few years.

2. a. Rachel's stunted growth is most likely a result of the pituitary gland's failure to produce HGH.

b. The pituitary gland, not the adrenal gland, produces HGH.

c. Reduced levels, not excess levels, of HGH stunt growth.

d. The pituitary gland, not the adrenal gland, produces HGH, and reduced levels, not excess levels, of HGH stunt growth.

3. c. Studies show that malnutrition can have a substantial negative impact and dietary supplements can have a positive influence on children's physical growth.

a. The nutritional environment can have a negative or a positive influence on the developing child's physical growth.

b. The nutritional environment can have a negative or a positive influence on the developing child's physical growth.

d. Studies on nutrition and physical growth show that malnutrition can have a substantial negative impact and dietary supplements can have a positive influence on children's physical growth.

4. c. Research indicates that children who are malnourished are less attentive and active as well as more susceptible to illness, all of which are factors that reduce opportunities for learning and for enhancing cognitive abilities.

a. Although the lack of specific nutrients, including vitamins A and D, is linked to lowered growth, no evidence exists to indicate that it directly reduces or limits cognitive development. It is far more likely that if the lack of these nutrients influences cognitive development, it does so indirectly by, for example, reducing energy and learning opportunities for the child.

b. Efforts to teach parents to engage in more supportive and stimulating caregiver-child interactions have been shown to promote learning and development in malnourished children, although providing adequate nutrition benefits intellectual development as well.

d. Although neuron formation, migration, and differentiation may be hampered by severe malnutrition, brain damage is sometimes reversible when sufficient nutrition is provided, perhaps because the brain has excess numbers of neurons and differentiation continues whenever learning takes place.

5. a. Studies suggest that nonorganic failure to thrive is increased as a result of the caregiver's lack of positive affect or support and arbitrary interactions.

b. Although failure-to-thrive syndrome may be partly a result of the child's genetic makeup, the condition is likely to be worsened by the way in which the caregiver responds to the child.

c. Infants with failure-to-thrive syndrome are not normal in many respects, including physical growth and responsiveness to stimulation.

d. By definition, nonorganic failure-to-thrive syndrome describes cases where no specific organic or other cause can be identified.

6. b. Anorexia nervosa is a self-imposed form of starvation in which the individual becomes dangerously thin and may have disrupted menstrual periods.

a. Although bulimia nervosa is an eating disorder, individuals suffering from this disorder are often normal in weight.

c. Although an individual suffering from cancer may be extremely thin and have disrupted menstrual periods, the fact that Leslie was extremely concerned about her weight suggests that she is suffering from an eating disorder.

d. Failure to thrive is a term applied to young children who are extremely low in weight.

7. b. Postnatal brain growth is largely a result of an increase in the size of neurons and the complexity of connections between neurons.

a. Neuron proliferation stops approximately one to two months before birth; therefore, postnatal brain growth cannot be due to an increase in the number of neurons.

c. Postnatal brain growth is largely a result of an increase in the size and complexity of neurons, not in glial cells.

d. Postnatal brain growth does result from an increase in neuron size, but not in neuron number.

8. c. An individual is able to learn because the brain is sensitive to experience-dependent information throughout life.

a. The ability to learn new information does not occur during a critical period but progresses throughout an individual's lifetime.

b. Neurons are sensitive to experience-expectant information during critical periods. The ability to learn new information is not limited to critical periods.

d. There is no type of information called experience-independent information.

9. c. Pediatricians in most nations now recommend that infants be placed on their backs or sides when being readied for sleep because research in many countries has shown that, when such practices are adopted, sudden infant death syndrome declines substantially.

a. Although improved nutrition may have many benefits for infant development, no research has demonstrated that use of vitamin and mineral supplements substantially reduces the risk of SIDS.

b. The opportunity to engage in nonnutritional sucking has not been shown to be related to a decline in SIDS.

d. Infants who are breast-fed seem to have a lower risk of SIDS than infants who are bottle-fed.

10. b. A child who can coordinate both hands to perform a complex task has developed functional asymmetry.

a. Neat pincer grasp describes the ability to make fine grasping movements with the fingers.

c. Ballistic reaching describes the ability to retrieve objects in the visual field rapidly and accurately.

d. Prereaching describes a newborn infant's attempt to reach and make contact with nearby objects.

11. a. Toddlers are more likely to engage in large-muscle activities such as pulling and pushing things than in small-muscle activities.

b. Toddlers are more likely to engage in large-muscle activities than in small-muscle activities such as coloring and drawing.

c. Toddlers are more likely to engage in large-muscle activities than in small-muscle activities such as cutting and pasting.

d. Toddlers are more likely to engage in large-muscle activities than in small-muscle activities such as sculpting with clay.

12. c. The ages at which motor milestones are achieved differ among some cultures depending on cultural and social influences.

a. The ages at which motor milestones are achieved differ among some cultures.

b. The order in which motor milestones are achieved is fairly consistent across cultures, but the ages at which they are achieved may differ.

d. Children in many cultures achieve milestones at different ages, but usually in a consistent order.

13. b. Incomplete ossification indicates that the bones are still maturing and that Stuart may even continue to grow.

a. Incomplete ossification of bones in children is not a sign of pathology but an indication that the individual has not yet reached maturity.

c. Incomplete ossification indicates further growth is possible. Since Stuart may still be growing, we really can't determine whether he will be shorter than most children his age.

d. Incomplete ossification of bones in children is not a sign of pathology but an indication that the child may still grow.

14. a. Late-maturing boys tend to report more negative feelings about themselves and tend to diplay more attention-getting behavior.

b. Early maturity enhances status and self-confidence in boys; such boys are therefore less likely to display childish, attention-getting behavior.

c. It is the late-maturing boys who are more likely to display childish, attention-getting behavior.

d. Boys mature between nine and seventeen years of age; therefore, it is unlikely that Jason has not yet matured.

15. b. Evidence suggests that youth who have the opportunity to recognize situations that are likely to lead to sexual activity are more comfortable about declining this activity if they prefer to do so.

a. A stressful family environment seems to be a factor that is correlated with early sexual activity.

c. the perception that agemates are sexually active seems to increase the likelihood that a young person will engage in such activity.

d. Extreme restrictiveness seems to be more likely to result in sexual activity than does good communication among parents and youth about such activity.

16. b. Girls who go through puberty earlier than their peers are more likely to experience greater social pressure and expectations from older peers and parents, resulting in higher levels of juvenile delinquency.

a. A 10 year old girl who has reached puberty would not be considered a late maturing girl.

c. A typical 10 year old would not be engaging in such activities.

d. Ten years old is young for a girl to enter puberty (which is implied by the activities described in this situation, given the information in the chapter).

17. b. Infant reflexes typically disappear as the brain matures and reorganizes. A five year old who exhibited infant reflexes most likely has some type of neurological disorder or cerebral palsy.

a. A normal child would not show the reflexes described at five years old.

c. Although motor control might be poor, in the event of a neurological disorder, the continued presence of infant reflexes would not allow us to predict this.

d. The continued presence of infant reflexes is not a symptom of Down syndrome.

18. b. Children who are exposed to passive smoke are more likely to die from SIDS than children who are not exposed to such smoke.

a. The lungs are developed at birth, although passive smoke might put a strain on the lungs.

c. Motor development is not influenced by passive smoke.

d. The pincer grasp is a normal part of motor development.