The smallest living organism which share the characteristics of both living and non-living matter are

1. Analyze the question You're asked for the smallest organism that shows features of both living and non-living things. That points to something on the borderline of life.

2. Explain the concept Viruses are acellular, meaning they have no cell structure. They consist of genetic material (DNA or RNA) wrapped in a protein coat.

Non-living features:

• They can be crystallized.
• They show no metabolism, growth, or reproduction outside a host cell.
• They have no cytoplasm, organelles, or cell membrane.

Living features:

• Once inside a host cell, they reproduce (replicate).
• They carry genetic material (DNA or RNA).
• They can mutate and evolve.
• They cause diseases (e.g. HIV, influenza, COVID-19).

3. Check each option

• A. Bacteria: These are single-celled prokaryotes. They are fully living, with metabolism and independent reproduction, so they have no non-living features.
• B. Fungi: These are eukaryotes (yeast, mushrooms, moulds) and are clearly living.
• C. Viruses: They are the smallest (about 20-300 nm) and sit between living and non-living matter, so this fits.
• D. Protozoa: These are single-celled eukaryotes such as Amoeba and Paramecium, and are clearly living.

4. Answer The correct option is C. viruses.

5. Exam tip Remember the phrase "a virus is alive only when it is inside a host." Whenever JAMB mentions "borderline between living and non-living" or "acellular," the answer is virus.