1 The term used to explain the situation where the cost of production decreases as the firm produces more goods is economies of scale.

Here are the solutions to your questions:

6.1 The term used to explain the situation where the cost of production decreases as the firm produces more goods is economies of scale.

6.2 The term that describes the situation whereby the cost of production increases as more units are produced is diseconomies of scale.

6.3 The term that describes a situation where the cost of production remains the same as more units are produced is constant returns to scale.

6.4

• The short run is a period in which at least one factor of production (input) is fixed and cannot be changed, while others are variable.
• The long run is a period in which all factors of production (inputs) are variable, meaning a firm can adjust all its inputs to change its scale of production.