A polygenic inheritance in human beings is

Options

A. skin colour
B. phenylketonuria
C. colour blindness
D. sickle-cell anaemia

Explanation

**Step-by-Step Text Solution:**

1. **Understanding Polygenic Inheritance**:
- Polygenic inheritance refers to a trait that is controlled by multiple genes, rather than a single gene. This results in a continuous range of phenotypes.

2. **Identifying Examples of Polygenic Traits**:
- In humans, traits such as skin color, height, and eye color are examples of polygenic inheritance. These traits do not follow simple Mendelian inheritance patterns.

3. **Analyzing the Given Options**:
- The question presents several traits: skin color, phenylketonuria, color blindness, and sickle cell anemia.
- Phenylketonuria is an autosomal recessive disorder caused by a mutation in a single gene.
- Color blindness is an X-linked recessive trait, also determined by a single gene.
- Sickle cell anemia is another autosomal recessive disorder, caused by a mutation in a single gene.

4. **Determining the Polygenic Trait**:
- Among the options, skin color is the only trait that is influenced by multiple genes, making it a classic example of polygenic inheritance.

5. **Conclusion**:
- Therefore, the correct answer to the question is "skin color," as it is the only trait listed that exhibits polygenic inheritance.

**Final Answer**: Skin color is a polygenic trait in human beings.

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