Viruses are:
o not alive because they can only carry out photosynthesis and not cellular respiration.
o alive because they mutate and change over time through evolution.
o not alive because they are not made of cells and require a host cell for reproduction.
o alive because they often contain dna.

The correct answer is C. Not alive because they are not made of cells and require a host cell for reproduction.

Explanation:

In biology, a living organism refers to any entity made of cells that is capable of reproduction, and growth; besides this, living organisms have a response to stimuli. Examples of living organisms include animals, plants, and bacteria. In the case of viruses, these are not by definition composed of cells although they contain genetic material. Moreover, viruses can only reproduce within the cells of another organism. Due to this, many viruses are not alive or are at the edge of life despite they can develop. Thus, it can be concluded viruses are "not alive because they are not made of cells and require a host cell for reproduction".