Final answer:
A fixed quantity of labor in a production function is called fixed labor input, which means the firm cannot change the amount of labor it uses.
Step-by-step explanation:
When looking at someone's production function, a fixed quantity of labor means that their firm is considered to be experiencing fixed labor input.
This implies that the firm is unable to change the amount of labor it uses and is operating with a constant number of workers.
In this scenario, the output of the firm will depend solely on the efficiency and productivity of the fixed labor input.