In mass flow substances whether in solution or in suspension are swept along at the same pace as in flowing river.

Answer

**Step-by-Step Text Solution:**

1. **Understanding Mass Flow**:
- Mass flow refers to the movement of bulk substances from one location to another due to a pressure gradient. This means that substances, whether they are dissolved in a solution or suspended in a medium, move together as a unit.

2. **Defining Key Terms**:
- **Solution**: A homogeneous mixture where one substance (solute) is dissolved in another (solvent).
- **Suspension**: A heterogeneous mixture where solid particles are dispersed in a liquid but are not dissolved.
- **Same Pace**: This implies that all substances in the mass flow move at the same speed, similar to how water flows in a river.

3. **Analyzing the Statement**:
- The statement claims that in mass flow, substances in solution or suspension are swept along at the same pace as in a flowing river.

4. **Comparing Mass Flow and River Flow**:
- In a flowing river, water carries along various substances, and they all move together at the same speed. Similarly, in mass flow, substances are also transported at the same rate due to the pressure differences.

5. **Conclusion**:
- Since both scenarios involve the movement of substances at the same pace, the statement is indeed **true**.

6. **Correct Statement**:
- The original statement is correct as it accurately describes the characteristics of mass flow.