The region consisting of long and severe winters and growing season consisting of few months of summers constitutes

Options

A. Savannah ecosystem
B. Taiga ecosystem
C. Tundra ecosystem
D. None of the above

Explanation

To solve the question regarding the region characterized by long and severe winters with a short growing season, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Ecosystem Options**:
- We have four options: savanna ecosystem, taiga ecosystem, tundra ecosystem, and none of the above.
- We need to analyze each option based on the climatic conditions described.

2. **Analyzing the Savanna Ecosystem**:
- The savanna is characterized by a warm climate with seasonal rainfall.
- It typically has a long growing season and is not known for long and severe winters.
- Therefore, the savanna ecosystem does not fit the description.

3. **Analyzing the Tundra Ecosystem**:
- The tundra is known for extremely cold temperatures, long winters, and a very short growing season.
- It has low precipitation and is characterized by permafrost.
- This aligns well with the description of long and severe winters and a short growing season.

4. **Analyzing the Taiga Ecosystem**:
- The taiga, or boreal forest, also experiences long winters but has a slightly longer growing season compared to the tundra.
- It has coniferous forests and is not as extreme in terms of cold as the tundra.
- While it has cold winters, it does not match the description as closely as the tundra does.

5. **Conclusion**:
- Based on the analysis, the ecosystem that best fits the description of long and severe winters and a short growing season is the **taiga ecosystem**.

### Final Answer:
The correct answer is **taiga ecosystem**.