The two unique characteristics that are required for something to be considered alive are:
a. It must have a metabolism: Metabolism refers to the set of chemical reactions that occur in an organism to maintain life. Living organisms must be able to take in nutrients, convert those nutrients into energy, and eliminate waste products.
c. It must reproduce: Reproduction is the process by which living organisms produce offspring. This can occur through sexual or asexual reproduction, but it is an essential characteristic of all living things.
While growth, a unique chemical structure, and movement are often associated with living organisms, they are not necessarily required for something to be considered alive. For example, viruses do not grow and do not have a metabolism, but they are still considered to be living because they are able to reproduce and evolve over time.