Because its living properties is that chemicall it is Nucleoprotein & non-living property is that it can be crystalised.

Why are viruses considered to be the missing link between the living and nonliving?

1. Characteristics of viruses:
Viruses are unique entities that possess characteristics of both living and nonliving things. They contain genetic material like living organisms, but they cannot carry out metabolic processes on their own.

2. Reproduction and replication:
Viruses require a host cell to reproduce and replicate. They inject their genetic material into host cells, hijacking the cellular machinery to make copies of themselves. This process is similar to how nonliving chemicals interact with living cells.

3. Lack of cellular structure:
Viruses lack a cellular structure, which is a defining feature of living organisms. They are simply genetic material enclosed in a protein coat, similar to nonliving particles.

4. Evolutionary debate:
The status of viruses as living or nonliving has been a topic of debate among scientists. Some argue that viruses should be considered living due to their ability to replicate and evolve, while others argue that they lack essential characteristics of life.

5. Role in disease:
Viruses are responsible for causing various diseases in living organisms. They can infect cells, disrupt normal cellular functions, and lead to illness. This ability to interact with living cells further blurs the line between living and nonliving entities.

6. Conclusion:
Overall, viruses exhibit a unique combination of characteristics from both living and nonliving entities, making them a fascinating subject of study in the field of biology. They serve as a bridge between the two realms, challenging our understanding of what it means to be alive.