The Sun causes tides just like the Moon does, although they are somewhat smaller. When the earth, Moon, and Sun line up—which happens at times of full Moon or new Moon—the lunar and solar tides reinforce each other, leading to more extreme tides, called spring tides.
The mucous membrane in the lung is there to capture and blocks foreign things dusts/dirt from entering the lungs. The membrane in the normal blood cell is to simply take in and out substances/gases like oxygen.
Explanation: The Himalayas are the world's tallest mountains. They are forming as two continents collide. The Appalachian Mountains are the remnants of a larger mountain range.