**Core Concept**
Premature birth and intrauterine growth restriction (IUGR) are two distinct conditions that affect fetal development. Premature birth refers to birth before 37 weeks of gestation, while IUGR refers to a condition where the fetus does not grow at a normal rate inside the uterus.

**Why the Correct Answer is Right**
Premature infants often exhibit characteristic physical features due to incomplete fetal development. One of the distinguishing features of premature infants is the presence of sole creases all over the feet. This is because the skin and underlying tissues have not yet fully developed, leading to the formation of creases and folds. In contrast, IUGR infants may exhibit growth restriction and may not necessarily have all the characteristic features of premature infants.

**Why Each Wrong Option is Incorrect**
* **Option B:** Breast nodule 2 mm is not a characteristic feature of premature infants. In fact, breast tissue is not fully developed in newborns, and nodules are not typically observed.
* **Option C:** Ear cartilage well formed - good clastic recoil is not a distinguishing feature of premature infants. While ear cartilage development is affected in premature infants, the presence of well-formed ear cartilage with good clastic recoil is not a characteristic feature.
* **Option D:** Skin glistening, thin is not a distinguishing feature of premature infants. While premature infants may have delicate skin, the presence of glistening, thin skin is not a specific characteristic feature.

**Clinical Pearl / High-Yield Fact**
Premature infants often have characteristic physical features, including skin folds, creases, and a smaller head circumference compared to gestational age. It is essential to recognize these features to diagnose premature birth accurately.

**Correct Answer: A. Sole creases all over feet.**