Which of these are false statements about calcium ?
I. It is required during the formation of the cell wall.
II. It accumulates in younger leaves.
III. Spindle fibers can't be formed with it.
IV. It is absolutely necessary for the synthesis of auxins.

Options

A. I and III
B. II and IV
C. II, III and IV
D. I, II and IV

Answer

To determine which statements about calcium are false, let's analyze each statement one by one:

### Step 1: Analyze Statement I
**Statement I:** "It is required during the formation of the cell wall."
- Calcium is indeed required for the formation of the cell wall as it helps in the stabilization of the cell wall structure through calcium pectate.
- **Conclusion:** This statement is **true**.

### Step 2: Analyze Statement II
**Statement II:** "It accumulates in younger leaves."
- Calcium does not accumulate in younger leaves; instead, it is typically found in older tissues and is mobile within the plant.
- **Conclusion:** This statement is **false**.

### Step 3: Analyze Statement III
**Statement III:** "Spindle fibers can't be formed with it."
- Calcium is not directly involved in the formation of spindle fibers during cell division. Spindle fibers are primarily made of tubulin, and while calcium plays a role in various cellular functions, it is not a component of spindle fibers.
- **Conclusion:** This statement is **true**.

### Step 4: Analyze Statement IV
**Statement IV:** "It is absolutely necessary for the synthesis of auxins."
- Auxins are primarily synthesized from tryptophan and are not directly dependent on calcium for their synthesis. While calcium may play a role in signaling pathways, it is not essential for auxin synthesis.
- **Conclusion:** This statement is **false**.

### Final Conclusion:
The false statements about calcium are:
- **Statement II:** "It accumulates in younger leaves."
- **Statement IV:** "It is absolutely necessary for the synthesis of auxins."