- Made up of cells
- Requires energy from an external source
- Uses ATP for cellular processes
- Grows and develops
Answer: (2) Requires energy from an external source
While all the listed options are characteristics of life, the unique aspect of photosynthesis is its ability to capture and utilize external energy (sunlight) to convert inorganic molecules (CO2 and H2O) into organic molecules (glucose) needed for growth and development.