Final answer:
A preterm newborn has fewer visible blood vessels, greater surface area in proportion to weight, and well-developed flexor muscles in the extremities.
Step-by-step explanation:
A preterm newborn has fewer visible blood vessels through the skin, compared to a full-term newborn. They also have greater surface area in proportion to weight and well-developed flexor muscles in the extremities. However, they have less subcutaneous fat in the neck and abdomen compared to a full-term newborn.