For identifying organisms through key usually

Options

A. Two contrasting characters are used
B. One similar character is studied
C. Two or more similar characters are used
D. Only one statement called lead is used

Answer

### Step-by-Step Solution:

1. **Understanding the Concept of Identification Keys**:
- Identification keys are tools used by scientists to classify and identify organisms based on their characteristics. They help in distinguishing between different species.

2. **Contrasting Characters**:
- The identification process typically involves comparing two contrasting characters. For example, one might compare whether a plant has broad leaves or needle-like leaves. This helps narrow down the possibilities.

3. **Use of Leads**:
- In the context of identification keys, a "lead" is a statement that presents two contrasting options. The user selects one option based on the observed characteristics of the organism.

4. **Classification Hierarchy**:
- Organisms are classified into a hierarchical system: Kingdom, Phylum, Class, Order, Family, Genus, and Species. This system, developed by Carl Linnaeus, helps in organizing biological diversity.

5. **Determining the Kingdom**:
- When identifying an unknown organism, scientists first determine whether it resembles plants or animals. If it has characteristics of animals, it is classified under the Kingdom Animalia. If it resembles plants, it falls under the Kingdom Plantae.

6. **Further Classification**:
- After determining the kingdom, the organism is further classified into its respective phylum, class, order, family, genus, and species based on its specific traits.