Final answer:
Cells are the smallest units of life, able to grow and reproduce on their own, and contain DNA, ribosomes, and cytoplasm. Viruses are unique entities that hijack host cells to reproduce and contain genetic material but lack other cellular components and cannot be considered living because they do not grow or maintain homeostasis on their own.
Step-by-step explanation:
Viruses are unique entities in biology, occupying a gray area between living and nonliving things. Here is the clarification for each characteristic:
- Smallest unit of life: This describes a cell. Viruses are not considered cells as they lack the essential components and cellular structure that define living cells.
- Hijacks host in order to reproduce: This is a characteristic of a virion, the individual virus particle. Viruses cannot reproduce on their own and must use the machinery of a host cell to replicate.
- Contains DNA, ribosomes, and cytoplasm: These are components found within a cell. Viruses may contain DNA (or RNA), but they do not have ribosomes or cytoplasm.
- Able to grow and reproduce on its own: Again, this describes a cell. Cells have the necessary structures and mechanisms to grow and reproduce independently, unlike viruses.
Viruses are often described as entities that require a host to reproduce, contain genetic material (DNA or RNA) inside a protein coat, and can evolve but lack the characteristics needed to be classified as fully living, such as metabolism, cellular structure, and the ability to maintain homeostasis.