Dicotyledons are characterised by presence of

Options

A. Tap root
B. Adventitious roots
C. Fibrous roots
D. Epiphytic roots.

Answer

### Step-by-Step Solution

1. **Understanding Dicotyledons**: Dicotyledons, commonly referred to as dicots, are one of the two major groups of angiosperms (flowering plants). They are characterized by having two cotyledons in their seeds.

2. **Identifying Key Characteristics**:
- **Cotyledons**: As mentioned, dicots have two cotyledons, which serve as the initial food source for the developing plant.
- **Root System**: Dicots typically exhibit a taproot system, where the primary root is long-lived and grows deeper into the soil, giving rise to secondary and tertiary roots.

3. **Comparing with Monocots**: In contrast, monocots (the other major group of angiosperms) have one cotyledon and usually possess a fibrous root system, where roots are short-lived and arise from the base of the stem.

4. **Analyzing Root Systems**:
- **Taproot System**: This is the primary root system in dicots, characterized by a thick main root that grows downwards.
- **Fibrous Root System**: This is found in monocots and is not a characteristic of dicots.
- **Adventitious Roots**: These can occur in both groups but are not a defining feature of dicots.
- **Epiphytic Roots**: These are specialized roots found in certain plants like orchids, which are not characteristic of dicots.

5. **Conclusion**: Based on the analysis, dicotyledons are primarily characterized by the presence of a **taproot system**.

### Final Answer
Dicotyledons are characterized by the presence of a **taproot system**.

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