Annual rings are distinct in plants growing in

Options

A. Tropical region
B. Temperate region
C. Grassland
D. Arctic region

Answer

### Step-by-Step Solution:

1. **Understanding Annual Rings**: Annual rings, also known as growth rings, are layers of wood produced by trees during a single growing season. They are visible in the cross-section of a tree trunk.

2. **Factors Influencing Annual Rings**: The formation of distinct annual rings is influenced by climatic variations such as temperature and rainfall. In regions where these factors change significantly throughout the year, trees exhibit more pronounced growth rings.

3. **Identifying the Regions**:
- **Tropical Region**: In tropical regions, the climate is relatively stable with little variation in temperature and rainfall throughout the year. As a result, trees do not form distinct annual rings.
- **Temperate Region**: Temperate regions experience significant seasonal changes, including variations in temperature and precipitation. This leads to the formation of distinct annual rings in trees.
- **Grassland**: Grasslands may not have the same level of tree growth or distinct seasonal changes as temperate forests, leading to less distinct rings.
- **Arctic Region**: While the Arctic has extreme conditions, the short growing season and limited tree growth can lead to less distinct rings.

4. **Conclusion**: Based on the analysis of the climatic conditions in each region, the most distinct annual rings are formed in the **temperate region**. Therefore, the correct answer is **option B: temperate region**.