The primary purpose of a brokerage account is to buy and sell various types of investments. Here is a detailed explanation of this answer:

1. Definition of a brokerage account:
A brokerage account is a type of investment account that allows individuals to buy and sell securities such as stocks, bonds, mutual funds, and exchange-traded funds (ETFs). It serves as a platform for investors to access the financial markets and engage in trading activities.

2. Buying and selling investments:
One of the main functions of a brokerage account is to facilitate the buying and selling of investments. Investors can use their brokerage accounts to purchase stocks or bonds issued by companies or governments, invest in mutual funds that pool money from multiple investors, or trade ETFs that represent a basket of securities.

3. Access to financial markets:
By having a brokerage account, individuals gain access to financial markets where they can participate in various investment opportunities. They can take advantage of market fluctuations, conduct research on different securities, and make informed investment decisions based on their financial goals and risk tolerance.

4. Investment diversification:
Brokerage accounts allow investors to diversify their portfolios by investing in a wide range of assets. They can allocate their funds across different investment types, sectors, and geographies, reducing the risk associated with having all their investments concentrated in a single asset class.

5. Monitoring and managing investments:
Brokerage accounts provide investors with tools and resources to monitor and manage their investments. They offer online platforms or mobile applications that allow users to track their portfolio performance, receive real-time market data, set up alerts for price movements, and execute trades at their convenience.

6. Investment research and analysis:
Many brokerage firms offer research and analysis tools to assist investors in making informed investment decisions. These resources may include company profiles, financial statements, analyst reports, and market news. Investors can use these tools to evaluate the potential risks and returns of different investments before making a trade.

In conclusion, the primary purpose of a brokerage account is to provide individuals with a platform to buy and sell various types of investments. It offers access to financial markets, facilitates investment diversification, and provides tools for monitoring and managing investments.