Which is NOT a living thing?

Step 1: Analyze the question We are asked to find the option that is NOT a living thing. So four options are living organisms, and one is not generally classified as living.

Step 2: Recall the characteristics of living things (MRS GREN)

• Movement
• Respiration
• Sensitivity (irritability)
• Growth
• Reproduction
• Excretion
• Nutrition

A living thing is made of cells and can carry out these functions on its own.

Step 3: Check each option

• A. Bacteria: Single-celled prokaryotes. They feed, respire, grow, and reproduce independently. Living.
• B. Fern: A plant (pteridophyte) that photosynthesizes, grows, and reproduces by spores. Living.
• C. Fungi: Organisms such as mushrooms, yeast, and moulds. They are cellular, feed by absorption, and reproduce by spores. Living.
• D. Protozoa: Single-celled eukaryotes such as Amoeba and Paramecium. They carry out all life processes. Living.
• E. Virus: Has no cell structure, just genetic material (DNA or RNA) inside a protein coat. It cannot respire, feed, grow, or reproduce on its own. It only reproduces inside a host cell. So it is considered non-living outside a host (it sits on the borderline between living and non-living).

Step 4: Answer The virus is the only one that is not truly a living thing, so the correct option is E.

Exam tip: Remember "viruses are acellular." If a question asks for the non-living or borderline item among organisms, think virus. They are only "alive" when they invade a host cell, so they are often called obligate parasites that behave like crystals outside a host.