Greater the concentration of reactants, `underline("slower the rate of reaction")`.

Explanation

To solve the statement "Greater the concentration of reactants, slower the rate of reaction," we need to analyze the relationship between the concentration of reactants and the rate of reaction.

### Step-by-Step Solution:

1. **Understanding the Reaction Rate**:
- The rate of a chemical reaction is influenced by the concentration of the reactants. A fundamental principle in chemical kinetics is that the rate of reaction is dependent on how often reactant molecules collide.

**Hint**: Recall that reactions occur when molecules collide with sufficient energy and proper orientation.
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