What structure governs the administrative and judicial functions within counties in Texas?

The commission form of government is correct as it specifically characterizes the governance structure utilized by counties in Texas. This model is distinct as it combines both administrative and judicial responsibilities within a single governing body typically composed of elected officials known as commissioners.

In this system, the commissioners manage various departments, allowing for overlapping jurisdiction in both executive and legislative matters. It streamlines decision-making processes at the county level because the same individuals handle the local administration, finance, and legislative actions necessary to run county services efficiently. This holistic approach facilitates a more integrated management of county issues, which is vital given the diverse and often complex needs of local populations.

The other choices do not accurately represent the structure used in Texas counties. The executive and legislative authority combined may imply overlaps, but it does not capture the specific operational framework of the commission form. The separation of powers, typically associated with the higher levels of government (like federal or state), is not applicable at the county level in the same way and does not reflect the functional dynamics within Texas counties. A parliamentary system is characterized by its distinct approach to governance, primarily seen at the national or state level and lacking relevance in the local county structure.