Which of the following system freely allows exchange of energy and matter with its environment?

Options

A. Closed
B. Isolated
C. Open
D. partially closed

Answer

To determine which system freely allows the exchange of energy and matter with its environment, we can analyze the three types of systems: open, closed, and isolated systems.

### Step-by-Step Solution:

1. **Define the Types of Systems:**
- **Open System:** This type of system allows both energy (heat) and matter to be exchanged with its surroundings. An example is a boiling pot of water where steam (matter) escapes and heat is transferred to the environment.
- **Closed System:** In a closed system, energy (heat) can be exchanged, but matter cannot. An example is a sealed container of gas where heat can flow in or out, but the gas itself cannot escape.
- **Isolated System:** An isolated system does not allow the exchange of either energy or matter with its surroundings. An example is a thermos bottle that is perfectly insulated.

2. **Identify the System that Allows Full Exchange:**
- Since the question asks for a system that allows both energy and matter to be exchanged with the environment, we focus on the open system.

3. **Conclusion:**
- The correct answer is the **open system**, as it is the only type that allows for the free exchange of both energy and matter with the environment.

### Final Answer:
The system that freely allows the exchange of energy and matter with its environment is the **open system**.