In Sonneratia many roots come out of the substratum and grow vertically upwards. They are
(a) Pneumatophores
(b) Prop roots
(c) Stilt roots
(d) None of the above

Options

A. Pneumatophores
B. Prop roots
C. Stilt roots
D. None of the above

Answer

To solve the question regarding the type of roots that grow vertically upwards in Sonneratia, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Context**: The question mentions Sonneratia, a genus of mangrove plants known for their unique adaptations to wetland environments.

2. **Identify the Root Characteristics**: The roots in question are described as growing vertically upwards from the substratum. This growth pattern indicates that they are negatively geotropic, meaning they grow against the force of gravity.

3. **Evaluate the Options**:
- **(a) Pneumatophores**: These are specialized roots that grow upwards and are typically found in mangrove species. They are adapted for gas exchange in waterlogged soils.
- **(b) Prop roots**: These roots grow downwards from the stem and provide support. They are positively geotropic.
- **(c) Stilt roots**: Similar to prop roots, these also grow downwards and help in supporting the plant. They are also positively geotropic.
- **(d) None of the above**: This option suggests that none of the provided answers are correct.

4. **Determine the Correct Answer**: Since the roots in Sonneratia grow vertically upwards and are adapted for gas exchange, the correct answer is (a) Pneumatophores.

5. **Final Answer**: The roots that come out of the substratum and grow vertically upwards in Sonneratia are **(a) Pneumatophores**.