Daughter will be colour blind when
(a) father is colour blind, mother is normal
(b) Mother is a carrier, father is normal
(c) Mother is a colour blind, father is normal
(d) Father is colour blind, mother is carrier

Options

A. father is colour blind , mother is normal
B. Mother is a carrier , father is normal
C. Mother is a colour blind , father is normal
D. Father is colour blind, mother is carried

Answer

To determine when a daughter will be colorblind, we need to understand the genetics behind color blindness, which is an X-linked recessive trait. Here’s a step-by-step solution to the question:

### Step 1: Understand the Genetics of Color Blindness
Color blindness is typically 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). For a female to be colorblind, she must inherit the colorblind allele from both parents.

### Step 2: Analyze Each Option
We will analyze each option to see under which conditions a daughter would be colorblind.

- **Option (a): Father is colorblind, mother is normal**
- Father: XcY (colorblind)
- Mother: XX (normal)
- Possible daughters: XX (normal) - No colorblind daughter.

- **Option (b): Mother is a carrier, father is normal**
- Mother: XcX (carrier)
- Father: XY (normal)
- Possible daughters: XX (normal) or XcX (carrier) - No colorblind daughter.

- **Option (c): Mother is colorblind, father is normal**
- Mother: XcXc (colorblind)
- Father: XY (normal)
- Possible daughters: XcXc (colorblind) - Colorblind daughter possible.

- **Option (d): Father is colorblind, mother is carrier**
- Father: XcY (colorblind)
- Mother: XcX (carrier)
- Possible daughters: XcX (colorblind) or XX (normal) - Colorblind daughter possible.

### Step 3: Conclusion
From the analysis, we can conclude that the daughter will be colorblind in the following scenarios:
- If the mother is colorblind (Option c).
- If the father is colorblind and the mother is a carrier (Option d).

However, the only option that guarantees a colorblind daughter is when the father is colorblind and the mother is a carrier (Option d).

### Final Answer
**The daughter will be colorblind when the father is colorblind and the mother is a carrier (Option d).**

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