Pinus sylvestris grows at low temperatures in Russia. The plant survives under such freezing conditions due to the presence of:

Options

A. Saturated lipids in plasma membrane
B. Glycoproteins in plasma membrane
C. Glycolipids in plasma membrane
D. Polyunsaturated lipids in plasma membrane

Explanation

To solve the question regarding how Pinus sylvestris survives in low temperatures in Russia, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Plant and Its Environment**:
- Pinus sylvestris, commonly known as Scots pine, is known to grow in cold climates, particularly in Russia where temperatures can drop significantly.

2. **Understand the Challenge of Low Temperatures**:
- In freezing conditions, plants face the risk of cellular damage due to ice formation within their cells, which can disrupt cellular functions and lead to death.

3. **Explore the Adaptations of Pinus sylvestris**:
- To survive in such extreme conditions, certain adaptations are necessary. One key adaptation is the presence of specific compounds in their cell structure.

4. **Identify the Antifreezing Components**:
- The plant contains **polyunsaturated lipids** in its plasma membrane and cell wall. These lipids play a crucial role in preventing ice formation and maintaining cellular integrity at low temperatures.

5. **Explain the Function of Polyunsaturated Lipids**:
- Polyunsaturated lipids help to maintain fluidity in the cell membranes even at low temperatures, which prevents the membranes from becoming too rigid and allows for normal cellular functions to continue.

6. **Eliminate Incorrect Options**:
- Other options such as glycoproteins, glycolipids, and saturated lipids do not provide the necessary antifreezing properties. Glycoproteins and glycolipids are primarily involved in cell recognition and signaling, while saturated lipids can lead to rigidity in membranes at low temperatures.

7. **Conclude the Correct Answer**:
- Therefore, the presence of **polyunsaturated lipids** is the key factor that allows Pinus sylvestris to survive in freezing conditions.

### Final Answer:
Pinus sylvestris survives under freezing conditions due to the presence of **polyunsaturated lipids** in its cell membranes.

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