Which phrase best describes a lichen?

• A. A single-celled autotrophic organism
• B. A parasitic relationship between two plants
• C. A type of moss found in damp environments
• D. A symbiotic association between a fungus and a photosynthetic partner

Answer: (D)

Verified step by step guidance

1. Understand the definition of a lichen: A lichen is a symbiotic association between two different organisms, typically a fungus and a photosynthetic partner such as algae or cyanobacteria.
2. Clarify the role of each partner: The fungus provides a protective structure and absorbs water and nutrients, while the photosynthetic partner produces food through photosynthesis.
3. Eliminate incorrect options: Review each option provided in the question and compare it to the definition of a lichen. For example, a lichen is not a single-celled autotrophic organism, nor is it a parasitic relationship between two plants, nor a type of moss.
4. Focus on the correct option: The correct description of a lichen is a symbiotic association between a fungus and a photosynthetic partner, as this matches the biological definition.
5. Conclude by emphasizing the importance of symbiosis: Highlight that lichens are an excellent example of mutualism, where both organisms benefit from the relationship, and they play important ecological roles such as soil formation and serving as bioindicators of environmental health.