What does contributing bio-factors mean?

Question

What does contributing bio-factors mean?

Answer 1

I'm pretty sure what you are referring to is a biological agent, anything from a plant to a human, that is influencing something else.  

Take for example the following question:  What are the bio-factors playing a role in the composition of the atmosphere?  A: Humans by burning fossil fuels and other pollutants in the atmosphere.  Plants are another bio factor because they take in CO2 and give off O2....

hope this helps