Because of the expenses of living in the cities and the drug usage.
Part A is B and Part B is D.
Answer:
Small pieces of rock that settle at the bottom of rivers, lakes, and streams. Can also contain dead animal and plant matter or fossils. A type of chemical weathering that forms when fossil fuels, coal, and oil are burned and produce oxides that are released into the air and react with sunlight and water.
Explanation:
