This lecture addresses several fundamental puzzles in cosmology, focusing on the interplay between dark matter, dark energy, and the universe's structure. The instructor begins by discussing the transition from quantum to classical states, emphasizing the challenges in understanding how classical structures emerge from quantum origins. Key topics include the role of inflation, the nature of dark energy, and the origins of matter-antimatter asymmetry. The lecture also explores the generation of primordial magnetic fields and the implications of these phenomena for cosmological models. The instructor presents a series of equations and theoretical frameworks, including the Maxwell equations in an expanding universe, to illustrate the dynamics of these cosmic elements. The discussion extends to the potential existence of extra dimensions and their relevance to current cosmological theories. Throughout the lecture, the instructor reflects on the complexities and unresolved questions in theoretical cosmology, ultimately suggesting that a deeper understanding of these issues is essential for advancing the field.