When an `"F"_(1)` individual is crossed with its either of the two parents, the cross is known as:

Options

A. Test cross
B. Back cross
C. Reciprocal cross
D. Monohybrid cross

Answer

To solve the question, "When an F1 individual is crossed with either of the two parents, the cross is known as:", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Terms**:
- F1 generation refers to the first filial generation, which is the offspring resulting from a cross between two parental (P) individuals.
- The terms "back cross," "test cross," "reciprocal cross," and "monohybrid cross" are important in genetics.

2. **Identify the Types of Crosses**:
- **Back Cross**: This is when an F1 individual is crossed back with one of its parents. This helps to determine the genotype of the F1 individual.
- **Test Cross**: This involves crossing an F1 individual with a homozygous recessive individual to determine the genotype of the F1.
- **Reciprocal Cross**: This involves switching the roles of the parents in two separate crosses.
- **Monohybrid Cross**: This focuses on a single trait and involves two parents differing in one trait.

3. **Analyze the Question**:
- The question specifically asks about crossing an F1 individual with either of its parents. This is the definition of a back cross.

4. **Conclude the Answer**:
- Therefore, the correct answer to the question is that when an F1 individual is crossed with either of the two parents, it is known as a **Back Cross**.

### Final Answer:
When an F1 individual is crossed with either of the two parents, the cross is known as a **Back Cross**.

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