Final answer:
To assess a newborn's feeding ability, focus on neonatal reflexes and respiratory rate, as these directly impact the ability to suckle and take nourishment effectively.
Step-by-step explanation:
In determining a newborn's ability to take nourishment by nipple and mouth, a nurse should primarily assess neonatal reflexes and respiratory rate. Newborns are born with a set of reflexes that are crucial for their survival, such as the sucking reflex, which allows them to feed effectively, and the rooting reflex, which helps them find a nipple by turning their head towards anything that strokes their cheek. The respiratory rate is also a critical factor, as it can indicate whether a newborn is stable and comfortable enough for feeding. It is less relevant to assess factors like the maternal age and education, room temperature and humidity, or even the newborn's size and weight for this specific function, though these factors might influence overall health and development.