If a certain traits allele frequency is 100% describe the genetic variation for that trait in the population

There is no variation, every individual in the population has the allele for the trait.

what's the question?

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.