recycling trash conserving water reducing air pollution protecting endangered species
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Some scientists think their new car fuel will produce fewer chemicals than burning gasoline. The scientists test their hypothesis by performing several trials to compare the fuels. If the results of the trials agree with their hypothesis, in which area will their research most likely help?
Possibilities:
- recycling trash
- conserving water
- reducing air pollution
- protecting endangered species

reducing air pollution