Which of the following best describes phonology?

Phonology is the branch of linguistics that focuses on the systematic organization of sounds in languages. It examines how sounds function and pattern in specific languages and the rules governing those sounds, including their combination and distribution. This aspect of language is crucial for understanding how spoken language forms are produced and perceived, as well as how they contribute to the identity of a particular language.

The other options describe different linguistic disciplines. The study of sentence structure relates to syntax, which involves how words combine to form phrases and sentences. The study of word formation pertains to morphology, which explores how words are formed and their internal structures. Finally, semantics deals with meanings in context, focusing on how language conveys meaning rather than the sounds used to convey that meaning. Thus, phonology's emphasis on the sound systems of languages makes it distinct from these other areas of study.