I am pretty sure that the atmosphere keeps the oxygen and light in it.
Most major European cities are located either on the sea or on a navigable river. This helped keep the city connected to the rest of the country and world, and offered more shipping and economic opportunities.
D. Greenhouse gas feddback
I'm not for sure but I believe this is the answer sorry if I get it wrong in advance
1.weathered materials from rocks and transported to the beach through wind and rivers
2.from rocks weathering and eroding over thousands and millions of years.
