Find out the correct statement.

Options

A. a) In lichens, the algal component is called phycobiont and fungal component is known as mycobiont, which are heterotrophic and autotrophic, respectively.
B. b) Viroid contain RNA of low molecular weight and protein coat
C. c) A virus contains bothe RNA and DNA
D. d) Viruses are obligatory parasites

Answer

To solve the question "Find out the correct statement," we need to analyze each of the provided statements one by one.

### Step-by-Step Solution:

1. **Analyze Statement A**:
- Statement A claims that in lichen, the algal component is called "pycobiont" and the fungal component is known as "mycobiont," and that they are heterotrophic and autotrophic respectively.
- **Correction**: The algal component is actually called "phycobiont" (not pycobiont) and is autotrophic, while the fungal component is called "mycobiont" and is heterotrophic. Therefore, this statement is incorrect.

2. **Analyze Statement B**:
- Statement B states that viroids contain RNA of low molecular weight and a protein coat.
- **Correction**: Viroids do contain RNA of low molecular weight, but they do not have a protein coat. Therefore, this statement is also incorrect.

3. **Analyze Statement C**:
- Statement C claims that a virus contains both RNA and DNA.
- **Correction**: Viruses can contain either RNA or DNA, but not both simultaneously. Thus, this statement is incorrect.

4. **Analyze Statement D**:
- Statement D states that viruses are obligatory parasites.
- **Explanation**: This statement is correct. Viruses cannot reproduce outside a host cell and are considered obligate parasites because they require a host to replicate and multiply.

### Conclusion:
The correct statement among the options provided is **Statement D: viruses are obligatory parasites.**