Problem: - These substances rise into the high atmosphere - They react with water and oxygen - This creates a more acidic rain - The rain with the high acid content falls. What might be the first step of the process?

A: Chemicals like sulfur dioxide and nitrogen are released into the air

Problem: - The seeds are dispersed by wind, animals, etc - The seeds reach the ground - Grow into new trees - These new trees produce seeds - The process repeats itself over and over - What might be the first step of the process?

A: A tree produces seeds

Problem: - The recyclable materials go to a recycling center - The recycling center further separates the materials - Large equipment compacts the materials into bales - The recyclable materials are shipped to other recycling centers - The other recycling centers further process the materials that center specializes in - The materials are purchased by manufacturers - The manufacturers process the recycled materials the same way they would use new materials - The recycled materials are incorporated into new products. What might be the first step of the process?

A: People separate different materials to be recycled

Problem: - The seeds are dispersed by wind, animals, etc - The seeds reach the ground - Grow into new trees - These new trees produce seeds - The process repeats itself over and over - What might be the first step of the process?

A:
A tree produces seeds