Which of the following will be colour blind ?

Options

A. XY
B. `X^(c )X^(c )`
C. `X^(c )X`
D. XX

Answer

To determine which of the given options will be colorblind, we need to understand the genetics of colorblindness, which is an X-linked recessive trait. Here’s a step-by-step solution:

### Step 1: Understand the Genetics of Colorblindness
Colorblindness is caused by a recessive allele located on the X chromosome. Males have one X and one Y chromosome (XY), while females have two X chromosomes (XX).

### Step 2: Analyze the Options
1. **XY**: This represents a normal male. Since males have only one X chromosome, if it carries the normal allele, he will not be colorblind.
- **Conclusion**: Not colorblind.

2. **XBXB**: This represents a female with two normal alleles. Since both X chromosomes carry the normal allele, this female will not be colorblind.
- **Conclusion**: Not colorblind.

3. **XBX**: This represents a heterozygous female (one normal allele and one colorblind allele). This female will be a carrier but will not express colorblindness because the normal allele is dominant.
- **Conclusion**: Not colorblind.

4. **XcXc**: This represents a female with two colorblind alleles. Since both X chromosomes carry the colorblind allele, this female will be colorblind.
- **Conclusion**: Colorblind.

### Step 3: Final Answer
Among the given options, the organism that will be colorblind is **XcXc**.

---