Which of the following can be made into crystal?
(a) A bacterium
(b) An amoeba
(c) A virus
(d) A sperm

Correct Answer: (c) Virus

Explanation:

Viruses are considered to be on the borderline between living and nonliving things because they show the properties of living when they are inside the host body. They have their own DNA and RNA  and have the ability to reproduce when inside the host body.

They have non-living properties because they do not have a cellular structure, undergo crystallization, and remain completely inactive outside the host cell.

When viruses come in contact with suitable plant, animal, or bacteria host cells, they show the characteristics of living organisms. They infect the cell and quickly multiply inside it. Therefore, it can be said that viruses lie on the borderline between living and non-living things.