Pain receptors in the skin send signals to the cns for processing. these pain receptors are an example of

afferent conducting or conducted inward or toward something (for nerves, the central nervous system; for blood vessels, the organ supplied).

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.