I. Many xerophytic plants have thick cuticle on leaf epidermis and sunken stomata
II. Some xerophytic plants have special photosynthetic pathway (CAM) that enables their stomata closed during day
III. Opuntia has spines (modified leaves) photosynthetic phylloclade (stem)
IV. all adapatation are genetically fixed in all organisms
V. all adapatation are genetically not fixed
Choose the combination of correct option

Options

A. I,II,III and IV
B. II,III,IV and V
C. III,IV,V and I
D. I,II,III and V

Answer

To solve the question, we need to evaluate each statement regarding xerophytic plants and their adaptations. Let's analyze each statement step by step.

### Step-by-Step Solution:

1. **Statement I: Many xerophytic plants have thick cuticle on leaf epidermis and sunken stomata.**
- **Analysis:** Xerophytic plants are adapted to dry environments. A thick cuticle helps reduce water loss, and sunken stomata minimize exposure to air, further preventing water loss.
- **Conclusion:** This statement is **correct**.

2. **Statement II: Some xerophytic plants have special photosynthetic pathway (CAM) that enables their stomata to close during the day.**
- **Analysis:** Crassulacean Acid Metabolism (CAM) is a photosynthetic adaptation that allows plants to open their stomata at night to take in CO2 and close them during the day to conserve water. This is a common adaptation in many xerophytes.
- **Conclusion:** This statement is **correct**.

3. **Statement III: Opuntia has spines (modified leaves) and photosynthetic phylloclade (stem).**
- **Analysis:** Opuntia, commonly known as prickly pear, has modified leaves in the form of spines to reduce water loss and a stem that performs photosynthesis, which is an adaptation to its arid environment.
- **Conclusion:** This statement is **correct**.

4. **Statement IV: All adaptations are genetically fixed in all organisms.**
- **Analysis:** Adaptations can be influenced by genetic factors, but they are not strictly fixed. Organisms can exhibit phenotypic plasticity, allowing them to adapt to varying environmental conditions.
- **Conclusion:** This statement is **incorrect**.

5. **Statement V: All adaptations are genetically not fixed.**
- **Analysis:** This statement aligns with the understanding that while some adaptations may have a genetic basis, many are not strictly fixed and can change based on environmental conditions.
- **Conclusion:** This statement is **correct**.

### Final Conclusion:
The correct statements are I, II, III, and V. Therefore, the combination of correct options is **1, 2, 3, and 5**.