Study the graphs above and answer the questions that follow regarding market structure and firm behavior.

4.15.1. The market structure depicted in the graph above is $\boxed{\text{perfect competition}}$.

4.15.2. Price is determined in the above market by the $\boxed{\text{interaction of market demand (D) and market supply (S)}}$. The equilibrium price (P1) is established at the point where the quantity demanded by all consumers equals the quantity supplied by all firms in the industry.

4.15.3. If new firms enter this market:

• The industry supply curve (S) will shift to the right.
• This increase in supply will lead to a decrease in the equilibrium market price (P1 will fall).
• The equilibrium market quantity (Q1) will increase.

4.16.1. The market structure depicted in the graph above is $\boxed{\text{perfect competition}}$.

4.16.2. The profit maximisation point in the above graph is $\boxed{\text{a}}$.

4.16.3. The demand curve in the graph (MR/AR/DD) is $\boxed{\text{perfectly elastic}}$. It is a horizontal line at the market price, indicating that the individual firm can sell any quantity at the prevailing market price without affecting it.

4.16.4. One characteristic of a perfect competitor is that there are $\boxed{\text{many buyers and sellers}}$. This means no single buyer or seller has enough market power to influence the market price.

4.16.5. Calculate the profit/loss of the individual firm above. Show ALL calculations.