______ help to stop substances from leaking across a tissue.Choose the option which files the blank correctly.

Options

A. Gap junctions
B. Adhering junctions
C. Tight junctions
D. Interdigitations

Answer

To solve the question "______ help to stop substances from leaking across a tissue," we need to identify the correct type of junction that prevents leakage between cells.

### Step-by-Step Solution:

1. **Understand the Types of Junctions**:
- We need to consider different types of cellular junctions that connect cells in tissues. The main types are gap junctions, adhering junctions, tight junctions, and interdigitation.

2. **Evaluate Gap Junctions**:
- Gap junctions are specialized connections that allow for communication between cells through cytoplasmic channels. They facilitate the movement of ions and small molecules but do not prevent leakage.
- **Conclusion**: Gap junctions do not fit the requirement.

3. **Evaluate Adhering Junctions**:
- Adhering junctions (or desmosomes) help to anchor cells together and provide structural support. They do reduce leakage to some extent but are not completely impermeable.
- **Conclusion**: Adhering junctions are not the best answer as they do not fully prevent leakage.

4. **Evaluate Tight Junctions**:
- Tight junctions are crucial for forming a barrier between epithelial cells. They create a seal that prevents substances from passing between cells, effectively stopping leakage across tissues.
- **Conclusion**: Tight junctions are the correct answer as they completely prevent leakage.

5. **Evaluate Interdigitation**:
- Interdigitation refers to the interlocking of cell membranes, which can enhance adhesion but does not provide a complete barrier to leakage.
- **Conclusion**: Interdigitation does not prevent leakage effectively.

### Final Answer:
The correct option to fill in the blank is **Tight Junctions**.