In an experiment involving three types of crosses, the following results were observed in F1 progeny:
Cross 1: Only one parental character is expressed.
Cross 2: Both the parental characters are partially expressed.
Cross 3: Both the parental characters are expressed.
Which of the following conclusions is most likely to be correct?

Options

A. Cross 1 represents codominance, cross 2 represents incomplete dominance and cross 3 represents complete dominance.
B. Cross 1 represents codominance, cross 2 represents complete dominance and cross 3 represents incomplete dominance.
C. Cross 1 represents complete dominance, cross 2 represents incomplete dominance and cross 3 represents codominance.
D. Cross 1 represents incomplete dominance, cross 2 represents codominance and cross 3 represents complete dominance.

Answer

To solve the question regarding the three types of crosses and their results in F1 progeny, we will analyze each cross step by step.

### Step 1: Analyze Cross 1
In Cross 1, it is stated that only one parental character is expressed in the F1 progeny. This indicates that one trait is dominant over the other.

**Conclusion for Cross 1:**
This situation is an example of **complete dominance**. In complete dominance, the dominant allele completely masks the effect of the recessive allele in the heterozygous condition.

### Step 2: Analyze Cross 2
In Cross 2, both parental characters are partially expressed in the F1 progeny. This means that neither trait is completely dominant over the other, leading to a blending of traits.

**Conclusion for Cross 2:**
This scenario is an example of **incomplete dominance**. In incomplete dominance, the heterozygous phenotype is a blend of the two parental traits, resulting in a third phenotype.

### Step 3: Analyze Cross 3
In Cross 3, both parental characters are fully expressed in the F1 progeny. This indicates that both traits are visible and neither is dominant over the other.

**Conclusion for Cross 3:**
This situation is an example of **co-dominance**. In co-dominance, both alleles in a heterozygote are fully expressed, resulting in offspring that display both parental traits distinctly.

### Final Conclusion
Based on the analysis of the three crosses, we can summarize the conclusions as follows:
- Cross 1: Complete dominance
- Cross 2: Incomplete dominance
- Cross 3: Co-dominance

Thus, the correct conclusion is that Cross 1 represents complete dominance, Cross 2 represents incomplete dominance, and Cross 3 represents co-dominance.