A virus isn't considered life because they do not follow all of the characteristics of life. This lists consists of:
order - meaning systems of cells
response to the environment - can sense, integrate senses, and response
reproduction - can create offspring
growth and development - do the cells grow and mature
regulation - there are mechanisms in place for heat control, thirst, etc
homeostasis - are able to maintain environmental equilibrium/steady state
energy processing - have the ability to convert sun to energy or process something chemically todo so.
If you go through this list, it's quite clear why a virus doesn't make the criteria for life. There is no order, they do not respond to the environment, there is no cell growth or development, they do not have mechanisms for heat, thirst, etc, and they do not maintain an environmental steady state.
order - meaning systems of cells
response to the environment - can sense, integrate senses, and response
reproduction - can create offspring
growth and development - do the cells grow and mature
regulation - there are mechanisms in place for heat control, thirst, etc
homeostasis - are able to maintain environmental equilibrium/steady state
energy processing - have the ability to convert sun to energy or process something chemically todo so.
If you go through this list, it's quite clear why a virus doesn't make the criteria for life. There is no order, they do not respond to the environment, there is no cell growth or development, they do not have mechanisms for heat, thirst, etc, and they do not maintain an environmental steady state.