Assertion :- Usually facilitated diffusion is carried out of those substances in which hydrophilic moiety is present
Reason:- Lipoidal nature of plasma membrane creates difficulty in passing of those substances in which hydrophilic moiety is present.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false

Answer

To analyze the given assertion and reason, we will break down the concepts involved in facilitated diffusion and the characteristics of the plasma membrane.

### Step-by-Step Solution:

1. **Understanding Facilitated Diffusion**:
- Facilitated diffusion is a type of passive transport that allows substances to cross membranes with the assistance of special proteins. It is primarily used for molecules that cannot easily pass through the lipid bilayer of the plasma membrane due to their size or polarity.

**Hint**: Remember that facilitated diffusion involves transport proteins that help move substances across the membrane.

2. **Assertion Analysis**:
- The assertion states that "usually facilitated diffusion is carried out of those substances in which hydrophilic moiety is present." This is true because many substances that require facilitated diffusion are polar or charged (hydrophilic) and cannot easily diffuse through the hydrophobic lipid bilayer.

**Hint**: Think about why polar substances struggle to pass through the lipid bilayer.

3. **Reason Analysis**:
- The reason states that "the lipoidal nature of the plasma membrane creates difficulty in passing of those substances in which hydrophilic moiety is present." This is also true, as the lipid bilayer is composed of hydrophobic tails that repel hydrophilic substances, making it difficult for them to pass through without assistance.

**Hint**: Consider the structure of the plasma membrane and how it interacts with different types of molecules.

4. **Evaluating the Relationship**:
- The assertion and reason are both true. The reason correctly explains why facilitated diffusion is necessary for hydrophilic substances, as their inability to cross the hydrophobic membrane without help is what necessitates the use of transport proteins.

**Hint**: Reflect on how the reason supports the assertion logically.

5. **Conclusion**:
- Since both the assertion and the reason are true, and the reason provides a correct explanation for the assertion, the correct answer is that both assertion and reason are true, and the reason is the correct explanation of the assertion.

### Final Answer:
Both assertion and reason are true, and the reason is the correct explanation of the assertion.