Source of minerals to young leaves

Options

A. Minerals absorbed by root hairs
B. Senescent leaves
C. Minerals present in the atmosphere
D. 1 and 2

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the sources of minerals that supply young leaves in plants.

2. **Identifying the Sources**:
- **Root Hairs**: The primary source of minerals for young leaves is through root hairs. Root hairs absorb water and minerals from the soil.
- **Senescent Leaves**: Another source of minerals is from senescent (older) leaves. These leaves are in the process of dying and can transfer their stored minerals to younger leaves.

3. **Mechanism of Mineral Transport**:
- **Absorption by Root Hairs**: Root hairs absorb minerals from the soil, which are then transported through the plant via the xylem.
- **Transfer from Senescent Leaves**: Mobile minerals such as phosphorus, nitrogen, sulfur, and potassium can be moved from older leaves to younger leaves. This process occurs because the older leaves are about to fall off, and the plant reallocates these nutrients to support the growth of younger leaves.

4. **Evaluating the Options**:
- **Option A**: Minerals absorbed by root hairs - This is correct.
- **Option B**: Senescent leaves - This is also correct.
- **Option C**: Minerals present in the atmosphere - This is incorrect, as plants do not absorb minerals directly from the atmosphere.
- **Option D**: One and two (both root hairs and senescent leaves) - This is correct.

5. **Conclusion**: The correct answer is **Option D** (one and two), as both root hairs and senescent leaves are sources of minerals for young leaves.