The smallest group among the options provided is population.
Here’s a quick breakdown of the terms:
- Population: A group of individuals of the same species living in a specific area.
- Community: A group of different populations (species) that live together in a specific area.
- Ecosystem: A community of living organisms interacting with their physical environment.
- Biome: A larger geographical area that is characterized by specific climate conditions and types of plants and animals.
Thus, a population is the smallest unit in this context.