The distinguishing anatomical features of stem are that they have

Options

A. multicellular haris, exarch xylem and exogenous lateral branched
B. multicellular haris, endarch xylem and exogenous lateral branched
C. unicellular hairs, xylem and exogenous lateral branches
D. multicellular hairs, endarch xylem and endogenous lateral branches

Answer

### Step-by-Step Solution:

1. **Identify the Anatomical Features of Stem**: The first step is to understand that the stem has specific distinguishing anatomical features that set it apart from other plant parts.

2. **Presence of Trichomes**: One of the key features of the stem is the presence of hair-like structures known as trichomes. These can be either multicellular or unicellular. In stems, trichomes are predominantly multicellular, which helps in various functions including the prevention of water loss.

3. **Type of Xylem**: The xylem in stems is characterized as endarch. This means that the protoxylem (the first-formed xylem) is located towards the center (inner side) of the stem, while the metaxylem (the later-formed xylem) is found towards the outer side. This arrangement is crucial for the efficient transport of water and nutrients.

4. **Branching Pattern**: Stems exhibit exogenous branching, meaning that branches arise from the outer layers of the stem. This is in contrast to roots, which typically show endogenous branching (where branches arise from within).

5. **Summarizing the Features**: Therefore, the distinguishing anatomical features of stems include:
- Multicellular trichomes (hairs)
- Endarch xylem arrangement
- Exogenous branching pattern

### Final Answer:
The distinguishing anatomical features of a stem are that they have multicellular hairs (trichomes), endarch xylem, and exhibit exogenous branching.

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