You are presented with the question "plants cell walls are readily broken down by what" and the following answer choices: 
- Heavy rains
 - heat energy
 - acetic acid
 - microbes
 - fossil fuels
 - heat
 - bacteria
 - chemicals

Now knowing that plants use cellulose for their cell walls and leaf blades contain cellulose and hemi-cellulose that are readily broken down by microbes, choose the best answer.


 

    microbes     