Which class of molecules functions as chemical signals?
o carbohydrates
o water
o hormones
o proteins

six grader is what i am ssorry

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.

c.           is the correct answer