The structure absent in monocot is

Options

A. Sieve tubes
B. Pith
C. Cambium
D. Vessels

Answer

To determine which structure is absent in monocots, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Monocots**: Monocots, or monocotyledons, are a group of flowering plants characterized by having one seed leaf (cotyledon). They typically exhibit specific structural features.

2. **Identify Structures Present in Monocots**:
- Monocots possess an epidermis, hypodermis, ground tissue, cortex, medulla, pericycle, and vascular bundles.
- In monocots, the xylem and phloem are found in the same vascular bundles, which are termed closed collateral vascular bundles.

3. **Identify Structures Absent in Monocots**:
- One of the key structures absent in monocots is the cambium layer, which is responsible for secondary growth in dicots.
- Additionally, monocots do not have pith, which is the central part of the stem in many dicots.

4. **Analyze the Options**:
- Option A: Safetives (not a relevant structure in this context)
- Option B: Pith (absent in monocots)
- Option C: Cambium (also absent in monocots)
- Option D: Basals (not a relevant structure in this context)

5. **Conclusion**: Since both cambium and pith are absent in monocots, but the question asks for a specific structure, the best answer is **Option B: Pith**, as it is a clear and definitive absence in monocots.

### Final Answer:
The structure absent in monocots is **Pith (Option B)**.

---