Name two mineral elements which are highly mobile and two which are relatively immobile,

Explanation

**Step-by-Step Solution:**

1. **Understanding Mobile and Immobile Elements**:
- Mobile elements are those that can move from older tissues to younger tissues in plants. This means that when there is a deficiency, the older leaves will show symptoms first because the nutrients are being redirected to the growing parts of the plant.
- Immobile elements, on the other hand, cannot move from older tissues to younger ones. Therefore, deficiency symptoms will appear first in the younger leaves.

2. **Identifying Highly Mobile Elements**:
- Examples of highly mobile mineral elements include:
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