The type of inheritance in which many traits of a character are spread across a gradient and the effect of each allele is additive, is

Options

A. codominance
B. monohybride out cross
C. polygenic inheritance
D. dihybrid test cross

Answer

**Step-by-Step Solution:**

1. **Understanding the Question:**
The question asks about a type of inheritance where multiple traits of a character are distributed across a gradient, and each allele contributes additively to the phenotype.

2. **Analyzing the Options:**
The options given are:
- Co-dominance
- Monohybrid outcross
- Polygenic inheritance
- Dihybrid test cross

3. **Evaluating Co-dominance:**
In co-dominance, both alleles in a heterozygote are fully expressed, leading to a phenotype that shows both traits distinctly (e.g., red and white flowers producing pink flowers). This does not fit the description of traits spread across a gradient.

4. **Evaluating Monohybrid Outcross:**
Monohybrid outcross refers to a genetic cross involving one trait with two alleles. It does not involve multiple traits or additive effects, so it is not the correct answer.

5. **Evaluating Polygenic Inheritance:**
Polygenic inheritance involves multiple genes contributing to a single trait, where each allele has an additive effect. This results in a continuous range of phenotypes (e.g., human height, skin color). This matches the description given in the question.

6. **Evaluating Dihybrid Test Cross:**
A dihybrid test cross involves two traits and does not specifically relate to the additive effects of multiple alleles for a single trait. Therefore, it is not the correct answer.

7. **Conclusion:**
Based on the analysis, the correct answer is **polygenic inheritance**. This type of inheritance is characterized by multiple genes contributing to a single trait, with each allele having an additive effect.

---