The lichens can be used

Options

A. as antibiotic and litmus
B. in perfumes and scent sticks
C. as food by man and reindeers
D. all of those

Answer

### Step-by-Step Solution:

1. **Understanding Lichens**:
- Lichens are a symbiotic association between two organisms: fungi and algae. This means that lichens are formed when these two different types of organisms live together in a close relationship.

2. **Uses of Lichens**:
- Lichens have several important uses, which include:
- **Antibiotics**: Some lichens produce compounds that have antibiotic properties, which can be beneficial in medicine.
- **Litmus**: Lichens can be used as natural indicators for pH levels, commonly known as litmus.
- **Perfume Industry**: Certain lichens are used in the production of perfumes and scent sticks due to their aromatic properties.
- **Food Source**: Lichens can be consumed by humans and animals, such as reindeers, making them a food source in some cultures.

3. **Conclusion**:
- Given the various uses of lichens, the correct answer to the question "The lichens can be used" would be that they are used in multiple ways, including as antibiotics, litmus, in the perfume industry, and as food. Therefore, the best option would be "all of these."