1. Cellular Organization: All living things are made up of one or more cells. These cells are the basic units of life, carrying out essential functions like metabolism and reproduction.
2. Metabolism: Organisms take in energy from their surroundings (either through sunlight or by consuming other organisms) and use it to grow, maintain themselves, and reproduce. This involves complex chemical reactions.
3. Growth and Development: Organisms grow and develop over time, increasing in size and complexity. This involves increasing the number of cells or the size of individual cells.
4. Reproduction: Organisms produce offspring, ensuring the continuation of their species. Reproduction can be sexual (involving two parents) or asexual (involving only one parent).
5. Response to Stimuli: Organisms react to changes in their environment. This includes things like moving towards food, away from danger, or adjusting to temperature changes.
It's important to note that some organisms, like viruses, don't meet all of these criteria, and are therefore debated as to whether they are truly alive.
