What is a key characteristic of the House of Representatives?

Members of the House of Representatives are elected for two-year terms, which is a fundamental characteristic of this legislative body. This short term length encourages representatives to be responsive to their constituents, as they must seek re-election every two years. This accountability to voters is a cornerstone of the democratic process in the United States.

In contrast, the other statements do not accurately represent the House. For instance, lifetime appointments refer to judges rather than members of the legislature, and the House has significantly more than 50 members; in fact, it comprises 435 representatives. While the House does play a significant role in tax legislation, it is not limited to this area, as it deliberates on a wide range of issues and proposed laws. Therefore, the correct answer highlights the unique and important aspect of the electoral cycle within the House of Representatives.