Bark does not include

Options

A. secondary xylem
B. secondary phloem
C. periderm
D. both a and b

Explanation

To answer the question "Bark does not include," we need to understand the composition of bark and its relationship with the vascular cambium. Here’s a step-by-step breakdown:

### Step 1: Define Bark
Bark is defined as the outer protective covering of a tree or plant. It serves as a protective layer against environmental factors and pests.

**Hint:** Remember that bark is the outermost layer of a tree.

### Step 2: Identify Components of Bark
Bark includes various tissues that are found outside the vascular cambium. The main components of bark are:
- Secondary phloem
- Periderm (which includes cork and cork cambium)
- Phallogen
- Phallum

**Hint:** Think about what layers are found outside the vascular cambium.

### Step 3: Understand the Role of Vascular Cambium
The vascular cambium is a layer of tissue that produces secondary xylem (wood) and secondary phloem. The secondary xylem is located inside the vascular cambium, while the bark is composed of tissues outside this layer.

**Hint:** The vascular cambium is crucial for growth and is the boundary between the bark and the wood.

### Step 4: Identify What Bark Does Not Include
Since bark is defined as the tissues outside the vascular cambium, it does not include:
- Secondary xylem (which is produced by the vascular cambium and is located inside it)

**Hint:** Focus on what is inside the vascular cambium to determine what bark excludes.

### Step 5: Conclusion
Based on the above understanding, we conclude that the bark does not include the secondary xylem.

**Final Answer:** Bark does not include secondary xylem.