Which one of the following is a taxonomical aid for identification of plants and animals based on similarities and dissimilarities

Options

A. Flora
B. Keys
C. Manuals
D. Catalogues

Answer

To solve the question, "Which one of the following is a taxonomical aid for identification of plants and animals based on similarities and dissimilarities?", we will analyze the options provided:

### Step-by-Step Solution:

1. **Understanding Taxonomical Aids**:
- Taxonomical aids are tools or methods used to identify and classify organisms based on their characteristics.

2. **Evaluating the Options**:
- **Option 1: Flora**
- Flora refers to a comprehensive description of plant species in a specific area. It mainly focuses on plants and does not specifically address the identification of animals or the comparison of similarities and dissimilarities.

- **Option 2: Keys**
- Keys are systematic tools used for the identification of organisms. They provide a series of choices that lead the user to the correct identification based on observable similarities and dissimilarities among the organisms. This option directly aligns with the requirement of the question.

- **Option 3: Manuals**
- Manuals are books that provide detailed descriptions of families, genera, and species of organisms within a certain area. While they are useful for identification, they do not specifically focus on the comparative aspect of similarities and dissimilarities.

- **Option 4: Catalogs**
- Catalogs are lists of organisms, usually organized in alphabetical order. They do not provide a method for identification based on characteristics, thus not fitting the criteria of the question.

3. **Conclusion**:
- After evaluating all the options, the best answer that fits the description of a taxonomical aid for the identification of plants and animals based on similarities and dissimilarities is **Option 2: Keys**.

### Final Answer:
**Option 2: Keys**