What is the scientific study that seeks to explain the universe's beginnings and structure?

The scientific study that seeks to explain the universe's beginnings and structure is cosmology. This branch of science delves into the large-scale properties of the universe as a whole, addressing fundamental questions such as how the universe originated, its overall shape, and its ultimate fate. Cosmology integrates various scientific disciplines, including physics and astronomy, to form models and theories regarding the universe's evolution, particularly relating to concepts such as the Big Bang and cosmic inflation.

Other fields, like physics, focus more broadly on matter, energy, and the fundamental forces of nature, while astronomy primarily studies celestial objects and phenomena. Geology, on the other hand, is concerned with the Earth, its structure, processes, and history, rather than the wider universe. Thus, cosmology specifically encompasses the study of the universe's origins and structure, making it the correct choice for this question.