In a lake , phytoplankton grow in abundance in

Options

A. Littoral zone
B. Limnetic zone
C. Profundal zone
D. Benthic region.

Explanation

To determine where phytoplankton grow abundantly in a lake, we need to analyze the different zones of a typical lake:

1. **Identify the Zones of a Lake**: A typical lake consists of three main zones:
- **Littoral Zone**: This is the area near the shore where sunlight penetrates, allowing aquatic plants to grow.
- **Limnetic Zone**: Also known as the pelagic zone, this is the open water area where light penetration is limited.
- **Benthic Zone**: This is the bottom of the lake, containing both flora (plants) and fauna (animals).

2. **Examine Each Zone for Phytoplankton Growth**:
- **Littoral Zone**: This zone has abundant sunlight, which supports the growth of aquatic plants, but it is not primarily known for phytoplankton.
- **Limnetic Zone**: This zone is characterized as the open water area. It is here that phytoplankton, such as algae, thrive due to the availability of nutrients and some light penetration.
- **Benthic Zone**: This zone is at the bottom of the lake and is generally not suitable for phytoplankton growth due to lack of light.

3. **Conclusion**: Based on the characteristics of these zones, phytoplankton grow abundantly in the **Limnetic Zone**.

Thus, the correct answer is the **Limnetic Zone**.