When a plant have two alleles of contrasting characters it is called :-

Options

A. Homozygous
B. Dioecious
C. heterozygous
D. Monoecious

Answer

To solve the question "When a plant has two alleles of contrasting characters, it is called:", we can follow these steps:

### Step 1: Understand the Terms
- **Alleles**: Different forms of a gene that can exist at a specific locus on a chromosome.
- **Contrasting Characters**: This refers to alleles that express different traits (e.g., tall vs. short).

### Step 2: Identify the Types of Alleles
- **Homozygous**: This term refers to having two identical alleles for a particular gene (e.g., TT or tt).
- **Heterozygous**: This term refers to having two different alleles for a particular gene (e.g., Tt).
- **Dioecious**: This term refers to plant species that have distinct male and female individuals.
- **Monoecious**: This term refers to plant species that have both male and female reproductive structures on the same individual.

### Step 3: Analyze the Options
- The question specifically asks for a situation where a plant has two alleles that are contrasting.
- From the definitions, **heterozygous** is the correct term because it describes a pair of alleles that are different (e.g., one dominant and one recessive).

### Step 4: Conclusion
Based on the definitions and analysis, the correct answer to the question is **heterozygous**.

### Final Answer:
**Heterozygous**

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