Which statements are true about the layers of the earth. Choose all that apply. 1. The mantle is the hottest, but not the most dense layer. 2. The inner core is the most dense and the hottest layer. 3. The mantle is hotter than the crust and cooler than the outer core. 4. The outer core is liquid like the inner core. 5. The crust is the least dense and the coolest layer.