Explanation:

According to the Law of Diminishing Returns, in a production function when more and more units of the variable factor are used, holding the quantities of a fixed factor constant, a point is reached beyond which the marginal product will diminish.

It is based on the following assumptions: 

a) No change in the technology used.

b) It is applicable in the short run only.

c) The output is measured in physical units or tonnes only.

d) All units of variable factors of production are homogenous.