1. Energy: All organisms require energy to carry out essential life processes like growth, movement, and reproduction. This energy is obtained from food, either through photosynthesis (in plants) or by consuming other organisms.

2. Water: Water is crucial for all life functions. It serves as a solvent, transport medium, and plays a role in regulating temperature and maintaining cell structure.

3. Shelter/Habitat: Organisms need a suitable environment, or habitat, that provides protection from predators, adverse weather conditions, and ensures access to resources like food and water.

4. Reproduction: Organisms need to reproduce to ensure the continuation of their species. This can happen through various methods, like sexual reproduction (involving two parents) or asexual reproduction (involving a single parent).