Answer:
The marginal rate of technical substitution will remain constant.
Explanation:
The marginal rate of technical substitution is the rate at which an input is substituted for others. For instance, it is the rate at which the amount of labor should be decreased to increase the amount of capital.
It represents the slope of an isoquant. When the inputs are perfectly substitutable, the isoquant is a straight line. In this situation, the marginal rate of technical substitution remains the same at all the points of the isoquants. The MRTS remains constant, though further information is needed to find out if it is high or low.