What of the following are true (T) or false (F) ?
(a) The plasma membrane has rigid structure.
(b) Membrane are useful for compartmentalisation in cells.
(c) Solid particle are ingested by pinocytosis.
(d) All molecules can pass easily through a biomembrane if they are water soluble.
(e) ATP is required for active transport.
(f) Sodium-potassium pump help to transport `Na^(+)` ions and `K^(+)` ions in both directions across a membrane.

Explanation

To determine whether each statement is true (T) or false (F), let's analyze them one by one:

### Step-by-Step Solution:

1. **Statement (a): The plasma membrane has a rigid structure.**
- **Analysis:** The plasma membrane is flexible and not rigid. It allows for fluid movement and is composed of a lipid bilayer. In contrast, the cell wall is the rigid structure found in plant cells.
- **Conclusion:** **False (F)**

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