Which of the following statement is false w.r.t adaptations?

Options

A. Many xerophytic plants have thick cuticle on leaf epidermis, sunken stomata
B. Some xerophytic plants have special photosynthetic pathway (CAM) that enables their stomata close during day
C. Opuntia has spines (modified leaves), photosynthetic phylloclade (stem)
D. All adaptations are genetically fixed in all organisms

Answer

To determine which statement is false with respect to adaptations, we will analyze each statement one by one.

1. **Statement 1**: Many xerophytic plants have thick cuticles on the leaf's epidermis and sunken stomata.
- This statement is true. Xerophytic plants are adapted to dry environments, and thick cuticles and sunken stomata help reduce water loss.

2. **Statement 2**: Some xerophytic plants have a special photosynthetic pathway that enables their stomata to close during the day.
- This statement is also true. Many xerophytes, such as succulents, utilize CAM (Crassulacean Acid Metabolism) photosynthesis, allowing them to open their stomata at night and close them during the day to conserve water.

3. **Statement 3**: Opuntia has spines, i.e., modified leaves, and photosynthetic stems known as phylloclades.
- This statement is true. Opuntia, commonly known as prickly pear, has spines that are modified leaves, and its stems are adapted for photosynthesis.

4. **Statement 4**: All adaptations are genetically fixed in all organisms.
- This statement is false. While many adaptations are genetically inherited, some can be influenced by environmental factors and may not be fixed across all individuals of a species.

5. **Statement 5**: Thick cuticles on leaf and sunken stomata are the adaptations of xerophytic plants.
- This statement is true and reiterates the adaptations mentioned in Statement 1.

After analyzing all statements, we can conclude that:

**The false statement is Statement 4: "All adaptations are genetically fixed in all organisms."**