Phenotype of an individual is reflected by the contribution of each allele, i.e., the effect of each allele is additive in/for:

Options

A. Flower colour in sweet pea
B. Fruit colour in summer squash
C. Skin colour in humans
D. Plant height in garden pea

Answer

To answer the question regarding the phenotype of an individual and the additive effect of alleles, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Phenotype**:
- The phenotype of an individual refers to the observable characteristics or traits, such as height, color, and shape. These traits are influenced by the genotype, which is the genetic makeup of the individual.

2. **Role of Alleles**:
- Alleles are different forms of a gene that can exist at a particular locus on a chromosome. Each individual inherits two alleles for each gene, one from each parent.

3. **Additive Effect of Alleles**:
- In certain traits, the contribution of each allele to the phenotype is additive. This means that the effects of the alleles combine to influence the phenotype rather than one allele completely masking the effect of another.

4. **Example of Additive Inheritance**:
- A classic example of additive inheritance is seen in quantitative traits, such as height in humans. If one allele contributes a certain amount to height and another allele contributes a different amount, the total height will be the sum of these contributions.

5. **Conclusion**:
- Therefore, the phenotype of an individual is reflected by the contribution of each allele, and the effect of each allele is additive in traits that exhibit continuous variation, such as height, skin color, and weight.

### Final Answer:
The effect of each allele is additive in traits that exhibit continuous variation.

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