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Positive photoropism is due to elongatio...

Positive photoropism is due to elongation of cells

A

More on illuminated side and less on shaded side

B

More on shaded side and less on illuminated side

C

Less on illuminated side and normal on shaded side

D

Normal on illuminated side and less on shaded side

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The correct Answer is:
**Step-by-Step Solution:** 1. **Understanding Phototropism**: Phototropism refers to the growth response of a plant towards light. The prefix "photo" means light, and "tropism" means movement or growth in response to a stimulus. 2. **Role of Auxin**: Auxin is a plant hormone that plays a crucial role in regulating plant growth. The specific type of auxin involved in phototropism is Indole-3-acetic acid (IAA). 3. **Light Direction and Auxin Distribution**: When light shines on a plant, auxin is distributed unevenly. It accumulates more on the shaded side of the plant and less on the illuminated side. 4. **Cell Elongation**: The accumulation of auxin on the shaded side stimulates the elongation of cells in that region. This elongation causes the plant to bend towards the light source. 5. **Identifying the Correct Option**: Given the options: - Option 1: More on illuminated side and less on shaded side - Option 2: More on shaded side and less on illuminated side - Option 3: Less on illuminated side and normal on shaded side - Option 4: Normal on illuminated side and less on shaded side The correct answer is **Option 2**: More on shaded side and less on illuminated side, as this describes the mechanism of positive phototropism accurately. 6. **Conclusion**: Positive phototropism occurs due to the elongation of cells on the shaded side of the plant, causing it to bend towards the light. ---
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