The third name in trinomial nomenclature is

Options

A. (a) variety
B. (b) subspecies
C. (c) mutant
D. (d) cultivar

Answer

**Step-by-Step Solution:**

1. **Understanding Trinomial Nomenclature**: Trinomial nomenclature is a system used in biological classification that includes three names. The first name represents the genus, the second name represents the species, and the third name represents either the subspecies or variety.

2. **Identifying the Components**:
- **First Name (Genus)**: This is the first part of the name and is always capitalized. For example, in *Brassica oleraceae Capitella*, *Brassica* is the genus.
- **Second Name (Species)**: This is the second part of the name and is written in lowercase. In the same example, *oleraceae* is the species.
- **Third Name (Subspecies or Variety)**: This is the third part of the name. It can refer to a subspecies in zoological nomenclature or a variety in botanical nomenclature. In the example, *Capitella* represents the variety.

3. **Examples of Trinomial Nomenclature**:
- For plants: *Brassica oleraceae Capitella* (Cabbage)
- For animals: *Aesop's Americanus vermiculatus* (Grass Pickerel)

4. **Correct Options**: In the context of the question, the third name can be referred to as either a subspecies or a variety. Therefore, both options A (variety) and B (subspecies) are correct.

5. **Incorrect Options**: The terms "mutant" and "cultivar" do not fit the definition of the third name in trinomial nomenclature. A mutant refers to a genetic change, and a cultivar is a plant variety that has been produced in cultivation by selective breeding.

6. **Conclusion**: The third name in trinomial nomenclature can be correctly identified as either a subspecies or a variety, making both options A and B correct.

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