According to paragraph 5, which of the following is a problem with Milankovitch's theory? A. It assures that the astronomical cycles have been in existence for billions of years. B. It cannot explain why glaciation has been a relatively rare occurrence in Earth's history. C. It cannot predict periods of glaciation in Earth's distant past. D. It assures that astronomical cycles have an effect on Earth's climate even during periods when there is no glaciation.