What was rudolph virchow’s contribution to the cell theory? he concluded that all cells come from preexisting cells. he concluded that cells are the basic units of structure and function of all living things. he concluded that all organisms are composed of cells. he concluded that all cells are similar in composition and metabolic activities.

He concluded that all cells come from preexisting cells.

answer; i believe the correct answer is (replication is not conservative);

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.