What is the function of the subheadings in "All About Sleep"? A. They answer the question "What Makes You Sleep?" and explain the different steps of the sleep cycle. They answer the question "What Makes You Sleep?" and explain the different steps of the sleep cycle. B. They provide definitions of technical terms related to the study of sleep. C. They provide links to information about sleep-related topics and expand on details in the text. D. They answer the question "Why Is Sleep Important?" and are followed by text that provides further details.