Which of the following is the example of sex-linked disease?

Options

A. AIDS
B. Colour blindness
C. Syphilis
D. Gonorrhoea

Explanation

To determine which of the following is an example of a sex-linked disease, we will analyze each option provided:

1. **AIDS**: This is caused by the Human Immunodeficiency Virus (HIV) and is not linked to sex chromosomes. Therefore, it is not a sex-linked disease.

2. **Color Blindness**: This is a condition that affects the ability to distinguish between certain colors, primarily red and green. It is caused by a defect in genes located on the X chromosome. Since males have one X chromosome (XY) and females have two (XX), color blindness is more common in males. This makes color blindness a sex-linked recessive disorder.

3. **Syphilis**: This is a sexually transmitted infection caused by the bacterium Treponema pallidum. It is not linked to sex chromosomes and therefore is not a sex-linked disease.

4. **Gonorrhea**: This is another sexually transmitted infection caused by the bacterium Neisseria gonorrhoeae. Like syphilis, it is not linked to sex chromosomes and is not a sex-linked disease.

Based on this analysis, the only option that qualifies as a sex-linked disease is:

**Answer: Color Blindness (Option 2)**