According to cohesion-tension-transpiration pull theory of ascent of sap, water is pulled upward through the sylem The cause of the pulls

Options

A. transpiratior
B. guttation
C. root pressure
D. condersation

Answer

**Step-by-Step Solution:**

1. **Understanding the Cohesion-Tension Theory**: The cohesion-tension theory explains how water moves upward through the xylem of plants. It involves two main concepts: cohesion (the attraction between water molecules) and tension (the pull created by transpiration).

2. **Role of Transpiration**: Transpiration is the process where water evaporates from the aerial parts of the plant, primarily from the leaves. This evaporation creates a negative pressure (or tension) in the leaf's air spaces.

3. **Creation of Suction**: As water evaporates from the leaves, it creates a deficit of water in the leaf. This deficit generates a suction effect, which pulls water upward from the xylem vessels in the roots.

4. **Movement through Xylem**: The water is pulled upward through the xylem due to the combined effects of cohesion (water molecules sticking together) and the tension created by transpiration. This allows water to move against gravity from the roots to the leaves.

5. **Conclusion**: Therefore, according to the cohesion-tension-transpiration pull theory, the primary cause of the upward pull of water through the xylem is transpiration.

**Final Answer**: The cause of the pull is transpiration.

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