Final answer:
The Speaker of the House is the chief presiding officer and most important party and house leader in the House of Representatives, elected at the start of every Congress.
Step-by-step explanation:
The chief presiding officer of the House of Representatives is known as the Speaker of the House. This individual is elected by the whole body of representatives at the beginning of every Congress on a straight party vote. The Speaker not only presides over the House's deliberations but also serves as the administrative head of the House, the leader of the majority party, and an elected representative of a single congressional district. The position carries substantial power, such as assigning bills to committees and ruling on House procedures. It's important to note that while the Constitution does not require the Speaker to be a member of the House, all Speakers so far have been members.