Which one of the following defects in man is due to sex-linked inheritance?

Options

A. Albinism
B. Colour blindness
C. Beri-beri
D. Rickets

Answer

**Step-by-Step Solution:**

1. **Understanding Sex-Linked Inheritance**:
- Sex-linked inheritance refers to traits or disorders that are associated with genes located on sex chromosomes (X or Y). In humans, males have one X and one Y chromosome (XY), while females have two X chromosomes (XX).

2. **Identifying the Options**:
- The question asks for a defect in humans that is due to sex-linked inheritance. Common examples of such defects include color blindness, hemophilia, and Duchenne muscular dystrophy.

3. **Analyzing Each Option**:
- **Albinism**: This condition is caused by mutations on autosomes (non-sex chromosomes) and is not sex-linked.
- **Color Blindness**: This condition is caused by mutations on the X chromosome. Since males have only one X chromosome, if they inherit the mutated gene, they will express the trait.
- **Berry Berry**: This is a nutritional deficiency (vitamin B1 deficiency) and is not linked to sex chromosomes.
- **Rickets**: This condition is caused by a deficiency of vitamin D and is also not linked to sex chromosomes.

4. **Conclusion**:
- Among the options analyzed, color blindness is the only defect that is due to sex-linked inheritance, specifically linked to mutations on the X chromosome.

5. **Final Answer**:
- The defect in man that is due to sex-linked inheritance is **color blindness**.

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