Assertion (A): A firm can face diminishing returns to a factor and constant returns to scale at the same time.

Reason (R): Returns to a factor and returns to scale describe different changes in inputs.

Explanation

1. 01

   Both are true: q = L^0.5 K^0.5 has diminishing MP of labour alone but constant returns when both double.

2. 02

   R explains A: one law varies one input, the other varies all, so they need not agree.