Identify the number of Mendelian disorders from the given list .
Sickle cell, anaemia , Colour blindness , Thalassemia , Phenylketonuria , Cystic Fibrosis , Haemophilia,

Options

A. Four
B. Six
C. Five
D. Three

Answer

To identify the number of Mendelian disorders from the given list, we will analyze each disorder mentioned and determine if it falls under the category of Mendelian disorders.

### Step-by-Step Solution:

1. **List the Disorders**: The disorders provided in the question are:
- Sickle Cell Anemia
- Color Blindness
- Thalassemia
- Phenylketonuria
- Cystic Fibrosis
- Hemophilia

2. **Define Mendelian Disorders**: Mendelian disorders are genetic disorders that are caused by alterations or mutations in a single gene. They follow Mendel's laws of inheritance.

3. **Analyze Each Disorder**:
- **Sickle Cell Anemia**: This is an autosomal recessive disorder caused by a mutation in the hemoglobin gene. **(Mendelian)**
- **Color Blindness**: This is a sex-linked recessive disorder affecting the ability to distinguish colors. **(Mendelian)**
- **Thalassemia**: This is an autosomal recessive disorder affecting hemoglobin production. **(Mendelian)**
- **Phenylketonuria (PKU)**: This is an autosomal recessive disorder that affects the metabolism of phenylalanine. **(Mendelian)**
- **Cystic Fibrosis**: This is an autosomal recessive disorder that affects the respiratory and digestive systems. **(Mendelian)**
- **Hemophilia**: This is a sex-linked recessive disorder affecting blood clotting. **(Mendelian)**

4. **Count the Mendelian Disorders**: After analyzing each disorder, we find that all six disorders listed are Mendelian disorders.

5. **Conclusion**: Therefore, the total number of Mendelian disorders from the given list is **6**.

### Final Answer:
The number of Mendelian disorders from the given list is **6**.