Which one of the following statements pertaining to plant structure is correct

Options

A. The sclerenchyma comprises of isodiametric cells and forms the major component with organs.
B. Xylem parenchyma cells are dead thin - walled with a cell wall made of pectin.
C. Tracheids are elongated or tube - like cells with thick and lignified walls and no protoplasm.
D. Parenchymatous cells provide mechanical support to the internal organs.

Answer

To solve the question regarding which statement about plant structure is correct, we will analyze each of the provided options one by one.

### Step 1: Analyze Option A
**Statement:** "Sclerenchyma comprises of isodimetric cells and forms the major component with organs."

**Analysis:** This statement is incorrect. Sclerenchyma is made up of thick-walled cells that are typically dead at maturity and provide mechanical support. The cells are not isodimetric; that characteristic belongs to parenchyma, which consists of living cells that can be isodiametric (equal in dimension from all sides).

**Conclusion:** Option A is incorrect.

### Step 2: Analyze Option B
**Statement:** "Xylem parenchyma cells are dead thin-walled with a cell wall made of pectin."

**Analysis:** This statement is also incorrect. Xylem parenchyma cells are living cells, not dead. They do have thin walls, but they are not primarily made of pectin; they are made of cellulose. The dead cells in xylem are typically tracheids and vessel elements.

**Conclusion:** Option B is incorrect.

### Step 3: Analyze Option C
**Statement:** "Tracheids are elongated or tube-like cells with thick and lignified walls and no protoplast."

**Analysis:** This statement is correct. Tracheids are indeed elongated, narrow, tube-like cells that have thick, lignified walls and are devoid of protoplasts (the living part of the cell). They are important for water conduction in plants.

**Conclusion:** Option C is correct.

### Step 4: Analyze Option D
**Statement:** "Parenchymatous cells provide mechanical support to the internal organs."

**Analysis:** This statement is incorrect. Parenchyma cells primarily function in storage, photosynthesis, and tissue repair. They do not provide mechanical support; that role is fulfilled by sclerenchyma and collenchyma.

**Conclusion:** Option D is incorrect.

### Final Conclusion
After analyzing all the options, the only correct statement is:
**"Tracheids are elongated or tube-like cells with thick and lignified walls and no protoplast."**