Which of the following statement is INCORRECT ?

Options

A. In the dicot root, the vascular cambium is completely secondary in origin.
B. Wood is the common name used for secondary xylem.
C. A mature sieve tube element lacks peripheral cytoplasm , a large vacuole and a prominent nucleus.
D. Lenticels are the aerating pores present in the bark of plants and are associated with gaseous exchange.

Answer

To determine which statement is incorrect, we will analyze each option provided in the question step by step.

### Step 1: Analyze the First Statement
**Statement:** In the dicot root, the vascular cambium is completely secondary in origin.

**Analysis:** This statement is correct. In dicot roots, the vascular cambium arises from the pericycle, which is a secondary meristem. Therefore, this statement is not the incorrect one.

### Step 2: Analyze the Second Statement
**Statement:** Wood is the common name used for secondary xylem.

**Analysis:** This statement is also correct. In botanical terms, wood is indeed the term used to refer to secondary xylem, which is produced by the vascular cambium. Hence, this statement is not incorrect.

### Step 3: Analyze the Third Statement
**Statement:** Mature sieve-tube elements have peripheral cytoplasm, a large vacuole, and a prominent nucleus.

**Analysis:** This statement is incorrect. Mature sieve-tube elements actually lack a prominent nucleus. While they do have peripheral cytoplasm and a large vacuole, the absence of a prominent nucleus is a defining characteristic of mature sieve-tube elements. Therefore, this statement is the incorrect one.

### Step 4: Analyze the Fourth Statement
**Statement:** Lenticels are the aerating pores present in the bark of plants and are associated with gaseous exchange.

**Analysis:** This statement is correct. Lenticels are indeed small openings in the bark of woody plants that facilitate gas exchange. Therefore, this statement is not incorrect.

### Conclusion
After analyzing all the statements, we conclude that the incorrect statement is the third one: "Mature sieve-tube elements have peripheral cytoplasm, a large vacuole, and a prominent nucleus."

### Final Answer
The incorrect statement is: **"Mature sieve-tube elements have peripheral cytoplasm, a large vacuole, and a prominent nucleus."**

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