What happens in mantle?

Could you elaborate on what occurs within the mantle? I'm particularly interested in understanding its geological functions and how it contributes to the overall structure and dynamics of the Earth. Could you provide some insight into the mantle's composition and the processes that take place within it? Additionally, I'm curious about how the mantle interacts with other layers of the Earth, such as the crust and the core, and how this interaction affects the Earth's surface features and geological events. Thank you for your assistance in clarifying this topic.