In a isobilateral leaf, two distinct patches of (A)____ are present above and below of each large (B)___ which extend towards upper and lower epidermic, respectively.

Answer

To solve the question, we need to identify the components of an isobilateral leaf, specifically what is found above and below the vascular bundle.

### Step-by-Step Solution:

1. **Understand the Structure of an Isobilateral Leaf**:
- An isobilateral leaf is characterized by having a symmetrical structure on both sides. This means that the mesophyll, the tissue between the upper and lower epidermis, is not differentiated into palisade and spongy layers as seen in dorsiventral leaves.

2. **Identify the Patches Above and Below the Vascular Bundle**:
- In an isobilateral leaf, there are two distinct patches of tissue that are present above and below the vascular bundle.

3. **Determine the Type of Tissue in the Patches**:
- The patches of tissue that are found above and below the vascular bundle are known as sclerenchyma. Sclerenchyma is a type of supportive tissue that provides strength and rigidity to the plant.

4. **Identify the Central Structure**:
- The central structure that the sclerenchyma patches are associated with is the vascular bundle. The vascular bundle contains xylem and phloem, which are responsible for the transport of water, nutrients, and food throughout the plant.

5. **Fill in the Blanks**:
- For blank (A), we fill in "sclerenchyma".
- For blank (B), we fill in "vascular bundle".

### Final Answer:
In an isobilateral leaf, two distinct patches of (A) **sclerenchyma** are present above and below of each large (B) **vascular bundle** which extend towards upper and lower epidermis, respectively.

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