Pls help if u know the ANSWER During a field trip, Luis notices that an old marble statue looks different from a new marble statue. The surface of an old statue is rough. The new statue is smooth and shiny. After doing research, Luis learns that marble undergoes chemical reactions with acid rain. The reactions cause some of the marble to be worn away. What did Luis observe on his field trip?

Erosion
Deposition
Physical weathering
Chemical weathering

the menstrual cycle – higher tier. negative feedback mechanisms affect the production of hormones in the menstrual cycle. oestrogen also stimulates the release of lh (luteinising hormone) from the pituitary gland, which in turn controls the production of progesterone.

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.

dna is a set of a gene held together by a chemical bond