Answer:
walk or bike reduces CO2
using computers helps save forests
treating sewage water conserves freshwater aquifers
Step-by-step explanation:
walking reduces CO2 by not using a car train or bus that puts out CO2
computers for note taking saves forests by reducing the amount of paper we use, therefore cutting down less trees to make the paper
treating sewage water and reusing it in factories conserves freshwater aquifers because we're recycling used water rather than continuing to use more and more freshwater.