Increased vigour of hybrid , over the parents resulting from the crossing of genetically unlike organisms is called

Options

A. Mutant
B. heterosis
C. Polypoid
D. Superiors

Answer

To solve the question regarding the increased vigor of hybrids over their parents resulting from the crossing of genetically unlike organisms, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for a term that describes the phenomenon where hybrids exhibit greater vigor compared to their parent organisms after crossing genetically different organisms.

2. **Analyzing the Options**:
- **Mutant**: This term refers to an organism that has undergone mutation, which is a change in its DNA sequence. This does not specifically relate to hybrid vigor, so this option is incorrect.
- **Heterosis**: This term describes the phenomenon where the offspring (hybrids) of genetically diverse parents show improved or superior qualities such as increased biomass, growth rate, and fertility compared to their parents. This is a strong candidate for the correct answer.
- **Polyploid**: This term refers to organisms that have more than two sets of chromosomes. While polyploidy can lead to certain advantages in plants, it does not specifically describe the vigor of hybrids over their parents. Thus, this option is incorrect.
- **Superior**: This term generally means higher in rank or quality but does not specifically relate to hybrid vigor. Therefore, this option is also incorrect.

3. **Selecting the Correct Answer**: Based on the analysis, the term that best describes the increased vigor of hybrids over their parents is **Heterosis**.

### Final Answer:
The correct answer is **Heterosis**.

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