A cross in which an organism showing a dominant phentype is crossed with the recessive parent in order to know its genotype is called:

Options

A. Monohybrid corss
B. Back cross`
C. Test crosses
D. Dihybrid corss

Answer

To solve the question, "A cross in which an organism showing a dominant phenotype is crossed with a recessive parent in order to know its genotype is called:", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Terminology**:
- Dominant phenotype: This refers to the observable traits that are expressed when at least one dominant allele is present.
- Recessive parent: This is an organism that carries two recessive alleles for a trait and will only express the recessive phenotype.

2. **Identify the Purpose of the Cross**:
- The goal of this cross is to determine the genotype of the organism with the dominant phenotype. The organism could either be homozygous dominant (TT) or heterozygous (Tt).

3. **Define the Types of Crosses**:
- **Monohybrid Cross**: This involves a cross between two organisms that differ in one trait.
- **Back Cross**: This is a cross between an F1 hybrid and one of its parents.
- **Test Cross**: This is specifically a cross between an organism with a dominant phenotype (unknown genotype) and a recessive organism to determine the genotype of the dominant organism.
- **Dihybrid Cross**: This involves two traits and is not relevant to this question.

4. **Apply the Definitions**:
- Since we are crossing a dominant phenotype with a recessive parent to determine the genotype, we can identify that this specific cross is a **Test Cross**.

5. **Conclusion**:
- The correct answer to the question is **Test Cross**.

### Final Answer:
The cross in which an organism showing a dominant phenotype is crossed with a recessive parent in order to know its genotype is called a **Test Cross**.

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