1. Cellular Organization: All living things are made up of one or more cells, the basic unit of life. These cells carry out the processes necessary for life, such as metabolism and reproduction.

2. Metabolism: Living organisms carry out a complex set of chemical reactions to obtain and use energy. This includes processes like breaking down food for energy (catabolism) and building complex molecules (anabolism).

3. Growth and Development: Living organisms increase in size and complexity over time. This can involve increasing the number of cells, increasing the size of individual cells, or both.

4. Reproduction: All living things reproduce, creating new individuals of the same kind. This can be through sexual reproduction (involving two parents) or asexual reproduction (involving only one parent).

5. Response to Stimuli: Living organisms can detect and respond to changes in their environment. These stimuli could include changes in temperature, light, chemicals, or the presence of other organisms.

These five characteristics are fundamental to what defines life, and are shared by all living things on Earth, from the smallest bacteria to the largest whales.