What causes moon phases and what is it we see from Earth?

The phases of the Moon that we see are caused by the relative positions of the Sun, Moon and Earth. The phase of the Moon is defined by the proportion of the Moon lit up by the Sun that is visible from Earth.

Explanation:

weathering - colorado river carves land in arizona to form the grand canyon. cracks form in a sandstone wall surrounding a house. a marble statue near the science museum is changing color due to rainfall

erosion - after a rainstorm, soil and rock piees litter the roadways. the sand dunes in the sahara desert are changing shape.

here's your answer.

well the answer is 2!