How may humans alter one of earths systems and ultimately cause changes to all of Earths Systems?m

Aresearcher is studying the science of attractiveness and asks volunteer test subjects to rank what trait they find most attractive in a person what type of variable is the dependent variable in this experiment

What's the waste product of electrons and pyruvate combining in fermentation?  

Which rate indicates the number of children that would be born per women if she were to live to the end of her child-bearing years