Lichens are

Options

A. Parasites
B. Saprophytes
C. Symbionts
D. Chemotrophs

Answer

### Step-by-Step Solution:

1. **Understanding Lichens**: Lichens are not single organisms; they are a combination of two different organisms that live together in a symbiotic relationship.

2. **Identifying the Organisms**: The two organisms that form lichens are fungi and algae. The fungi provide structure and protection, while the algae perform photosynthesis to produce food.

3. **Defining the Relationship**: The relationship between the fungi and algae in lichens is called symbiosis. In this relationship, both organisms benefit from each other.

4. **Classifying Lichens**: Given that lichens are formed by the symbiotic relationship between fungi and algae, they are classified as symbionts.

5. **Eliminating Other Options**:
- Lichens are not parasites because they do not harm their partner organisms.
- They are not saprophytes, as saprophytes feed on dead organic matter.
- They are not chemotrophs, which obtain energy from chemical compounds.

6. **Conclusion**: Therefore, the correct classification of lichens is that they are symbionts.

### Final Answer:
Lichens are symbionts.

---