Which of these genotypes are of homozygous individuals ?

Options

A. AABBCC
B. AAbbCC
C. AABBcc
D. All of these genotypes

Answer

To determine which of the given genotypes are homozygous individuals, we need to understand what "homozygous" means. A homozygous individual has two identical alleles for a particular gene, which can either be both dominant or both recessive.

### Step-by-Step Solution:

1. **Define Homozygous Condition**:
- Homozygous means having two identical alleles for a specific gene. This can be represented as either:
- Homozygous dominant (e.g., AA)
- Homozygous recessive (e.g., aa)

2. **Analyze the Options**:
- We will examine each option provided to see if both alleles for each gene are the same.

3. **Option A**: A, A; B, B; C, C
- For gene A: Both alleles are A (homozygous).
- For gene B: Both alleles are B (homozygous).
- For gene C: Both alleles are C (homozygous).
- **Conclusion**: This option is homozygous.

4. **Option B**: A, A; b, b; C, C
- For gene A: Both alleles are A (homozygous).
- For gene b: Both alleles are b (homozygous).
- For gene C: Both alleles are C (homozygous).
- **Conclusion**: This option is also homozygous.

5. **Option C**: A, A; B, B; c, c
- For gene A: Both alleles are A (homozygous).
- For gene B: Both alleles are B (homozygous).
- For gene c: Both alleles are c (homozygous).
- **Conclusion**: This option is also homozygous.

6. **Final Conclusion**:
- All three options (A, B, and C) consist of homozygous individuals since all alleles for each gene in each option are identical.
- Therefore, the answer is **D. All of these genotypes are homozygous individuals**.