Correct Answer: D

Rationale: Preterm newborns, like Cheryl, experience a higher percentage of REM sleep compared to full-term newborns. This is because REM sleep plays a critical role in brain development, and preterm infants have an increased need for brain development due to their early arrival. Therefore, Cheryl, as a preterm newborn, is most likely to experience the greatest percentage of REM sleep among the individuals listed.

Correct Answer: C

Rationale: One strength of the cross-sectional design is that it is not plagued with dropout or practice effects. This is because cross-sectional studies assess different individuals at the same point in time, eliminating the risk of participants dropping out or improving due to repeated measures.

Correct Answer: A

Rationale: By the twelfth week of pregnancy, the sex of the fetus can be detected with ultrasound. Ultrasound technology allows for visualization of the developing fetus and identification of physical characteristics, such as sex, during prenatal appointments.

Correct Answer: C

Rationale: Offering a sugar solution while gently holding the baby can help reduce the newborn's discomfort during circumcision. This method has been found to effectively decrease pain perception and can provide some comfort to the baby during the procedure. Stimulating the Babinski reflex, playing loud music to distract the baby, and assuming newborns have low sensitivity to pain are not recommended strategies for reducing discomfort during circumcision.

Correct Answer: D

Rationale: During the period of the embryo, the endoderm becomes the digestive system, lungs, urinary tract, and glands. The endoderm is one of the primary germ layers that give rise to various internal organs in the developing embryo. It plays a crucial role in the formation of organs such as the digestive system, respiratory system, and glandular structures.