When Baby Ian is held horizontally on his back, he sometimes makes an "embracing" motion by arching his back, extending his legs, throwing his arms outward, and then bringing his arms in toward his body. Ian is demonstrating the __________.

Correct Answer: B

Rationale: Baby Ian is demonstrating the Moro reflex. The Moro reflex is a normal newborn reflex that occurs when a baby feels like they are falling or losing support. It is characterized by arching the back, extending the legs, throwing the arms outward, and then bringing the arms in toward the body. This reflex is a primitive survival instinct that typically disappears around 6 months of age. Choice A, palmar grasp, involves the baby's fingers closing around an object when it touches their palm. Choice C, tonic neck reflex, involves the baby assuming a fencing position when their head is turned to one side. Choice D, Babinski reflex, is characterized by the fanning out and curling of the baby's toes when the sole of the foot is stroked.

Correct Answer: A

Rationale: Impaired brain functioning is a major contributor to Sudden Infant Death Syndrome (SIDS). Research has shown that abnormalities in the brainstem, which controls automatic functions like breathing and heart rate, can play a role in SIDS cases. As such, mounting evidence suggests that compromised brain functioning is a significant factor in the occurrence of SIDS. Choices B, C, and D are incorrect. Higher-than-average birth weight, organized and patterned sleep behavior, and a family history of chromosomal abnormalities are not identified as major contributors to SIDS according to the provided information.

Correct Answer: D

Rationale: Sensitivity to touch emerges early prenatally and is well-developed at birth. Newborn babies have a well-developed sense of touch, which is crucial for bonding with their caregivers and exploring their environment. This sensitivity to touch helps babies respond to comforting sensations such as gentle strokes and cuddles. Visual acuity, color vision, and depth perception are sensory capabilities that develop and mature after birth, not prenatally. While important for interacting with the environment, they are not as well-developed at birth as sensitivity to touch.

Correct Answer: C

Rationale: Three-month-old Jefferson will likely listen longer to human speech compared to nonspeech sounds because infants have a natural preference for speech sounds. This preference is believed to be attributed to their biological readiness to learn language and communicate with others. Choice A is incorrect because voices are a form of human speech, which is preferred over pure tones. Choice B is incorrect as noises do not necessarily engage infants' attention as effectively as human speech. Choice D is incorrect because Jefferson is more likely to listen longer to his native language rather than a foreign language at this early age.

Correct Answer: D

Rationale: The correct answer is D because investigators who study development aim to identify the factors that influence consistencies and transformations in people from conception to death. This goal encompasses various domains such as physical, cognitive, emotional, and social development, highlighting the comprehensive nature of developmental research. Choices A, B, and C are incorrect as they do not align with the overarching goal of developmental researchers, which is to understand the factors influencing individuals throughout their lifespan, rather than focusing solely on genetic factors, environmental factors related to disease, or abnormal development in specific age groups.