Final answer:
None of the statements is universally true for all markets in the long run. Market behavior is influenced by both short-term volatility and long-run trends, with supply and demand elasticity contributing to these patterns, and stock prices following a 'random walk with a trend'.
Step-by-step explanation:
In the context of market behavior and price movements, none of the statements given are universally true in the long run. In the case of market trends, they often persist over time but are not guaranteed to do so. Similarly, while short-term fluctuations may often dominate market behavior in the short run, this is not a rule that must hold in the long run. Unpredictable events can have a significant impact on markets, and it is incorrect to say that their impact is negligible. Lastly, market prices do not always revert to historical averages; they are influenced by a myriad of factors that can cause them to deviate significantly from past averages.
The principle to understand here is that supply and demand are inelastic in the short term, leading to greater volatility in prices. However, in the long term, supply and demand tend to be more elastic, allowing for greater adjustment in quantities rather than prices.
The case of stock prices operates under a similar principle called a "random walk with a trend," meaning that day-to-day movements are unpredictable, but over a long period, there tends to be a general upward trend.