Answer the following question given this paragraph: 

♦ Many industrial processes for preparing compounds use “continuous-flow reactors,” which are chemical reaction vessels in which the reactants are mixed and allowed to react as they flow along a tube. The products are removed at a certain distance from the starting point, when the reaction is nearly complete. The key operating parameters in a continuous-flow reactor are temperature, reactor volume, and reactant flow rate. As an industrial chemist, you think you have successfully modified a particular process to produce a higher product yield by substituting one reactant for another. The viscosity of the new reactant is, however, greater than that of the initial reactant.


Q: Continuous-flow reactors are chemical reaction vessels in which the what are mixed and allowed to react as they flow along a tube?

 Choices:

- reactives

- generators

- propellants

- reactants

A:
reactants
