Final answer:
Business competition may require a licence in specific industries, but not universally. Erecting barriers to entry is not characteristic of perfect competition but rather of less competitive market structures, and can lead to sustained profits for existing businesses by preventing new entrants.
Step-by-step explanation:
Business competition involves various strategies and activities that firms may engage in to gain a larger share of the market or maintain their existing market power. Not all aspects mentioned in the question are true for all forms of competition or market structures. Firstly, the need for a licence is typically related to specific industries and legal requirements, and not all businesses require one. Secondly, an active attempt to gain the market power of perfect competition is somewhat paradoxical, as perfect competition implies that no single firm has significant market power due to the presence of many competitors, free entry and exit, and homogeneous products. Thirdly, erecting barriers to entry is a strategy more associated with monopolies or oligopolies rather than perfectly competitive markets, where barriers are typically low or non-existent. Barriers can include legal restrictions, economies of scale, control of key resources, or intellectual property rights. Lastly, profits can result from business competition in various market structures; however, in perfect competition, profits are typically zero in the long run due to free entry and competition driving down prices to the level of costs. Profits act as a signal for new firms to enter an industry, which they do until economic profits are eliminated. However, in situations where barriers to entry are high, incumbent firms can sustain profits because it is difficult for new competitors to enter the market.