Final answer:
The student nurse demonstrates an understanding of neonatal assessment by correctly assessing the baby's heart rate using a stethoscope.
Step-by-step explanation:
An action by the student nurse that demonstrates an understanding of neonatal assessment is correctly assessing the baby's heart rate using a stethoscope.
The heart rate is one of the criteria assessed in the Apgar test for newborns. It is an important indicator of the baby's well-being and transition from the womb. Scores for heart rate are assigned based on the baby's heart rate at 1 minute and 5 minutes after birth.
By correctly using a stethoscope to assess the baby's heart rate, the student nurse is demonstrating an understanding of neonatal assessment.