All living organisms on the earth constitute :

Options

A. biome
B. biosphere
C. population
D. community

Explanation

To answer the question "All living organisms on the earth constitute:", we need to analyze the options provided and understand the definitions of each term.

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the term that encompasses all living organisms on Earth.

2. **Evaluating the Options**:
- **Option 1: Biome**: A biome refers to a large ecological area on the Earth's surface, with distinct plant and animal groups adapted to the environment. Biomes include deserts, grasslands, and forests. While biomes contain living organisms, they do not encompass all living organisms on Earth.
- **Option 2: Biosphere**: The biosphere is the global sum of all ecosystems. It is the zone of life on Earth, a closed system that includes all living organisms and their relationships with the environment (atmosphere, lithosphere, and hydrosphere). This is the correct answer as it includes all living organisms.
- **Option 3: Population**: A population refers to a group of individuals of the same species living in a specific area. For example, all humans (Homo sapiens) in a city would be a population. This does not represent all living organisms.
- **Option 4: Community**: A community consists of different populations that live together in a defined area. It includes various species but does not encompass all living organisms globally.

3. **Conclusion**: After evaluating all the options, the term that represents all living organisms on Earth is **Biosphere**.

### Final Answer: **Biosphere**

---