Final answer:
The Apgar score assesses the general well-being of a newborn. The heart rate criterion is an important component of the score. In this case, the newborn would receive an Apgar heart rate score of 2, which is normal.
Step-by-step explanation:
The Apgar score is a method used to assess the general well-being of a newborn immediately after birth. It evaluates five criteria: appearance (skin color), pulse (heart rate), grimace (reflex), activity (muscle tone), and respiration. Each criterion is assigned a score of 0, 1, or 2. The scores are added together to determine the overall Apgar score. In this case, since the newborn's heart rate is 90/min at the 5-minute mark, the baby's Apgar heart rate score would be 2, which is considered normal.