In which group of plants are the guard cells kidney-shaped, and in which group are these dumb bell-shaped ?

Explanation

**Step-by-Step Solution:**

1. **Understanding Guard Cells**: Guard cells are specialized epidermal cells located on the surface of leaves and stems. Their primary function is to regulate gas exchange and transpiration in plants.

2. **Formation of Stomata**: These guard cells work together to form stomatal pores or openings. These stomata are crucial for the exchange of gases (like oxygen and carbon dioxide) and for the loss of water vapor from the plant.

3. **Identifying Plant Groups**: There are two main groups of flowering plants: monocots and dicots.

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