In terms of the sciences, there are seven requirements that an organism must fulfill in order to be considered "alive":

1. The entity must be made up of cells.
2. The entity must respond to the environment.
3. The entity must be organized, that is, it must have a structure.
4. The entity must use energy for growth and maintenance (a process called metabolism).
5. The entity must reproduce.
6. The entity must grow and develop.
7. The entity must adapt to the environment.