True about Down’s syndrome – a) Hypertoniab) Simian creasec) Lymphedemad) Mongoloid slant

**Core Concept**
Down's syndrome is a genetic disorder caused by an extra copy of chromosome 21, leading to distinct physical and developmental characteristics. The condition is associated with various **congenital anomalies** and **facial dysmorphisms**.

**Why the Correct Answer is Right**
The correct answer is related to the characteristic features of Down's syndrome, which include **simian crease** (a single deep crease across the palm) and **mongoloid slant** (upward slanting of the eyes). These features are due to the underlying **genetic abnormality** affecting **embryonic development**.

**Why Each Wrong Option is Incorrect**
**Option A:** Hypertonia is not a characteristic feature of Down's syndrome; in fact, **hypotonia** is more commonly associated with the condition.
**Option C:** Lymphedema is not a typical feature of Down's syndrome, although it can occur in various other conditions.

**Clinical Pearl / High-Yield Fact**
Down's syndrome is often associated with **congenital heart defects** and **intellectual disability**. Recognizing the characteristic physical features, such as simian crease and mongoloid slant, can aid in early diagnosis.

**Correct Answer:** B. b and d (Simian crease and Mongoloid slant)